166-642: The Cullinan Diamond is the largest gem-quality rough diamond ever found, weighing 3,106 carats (621.20 g), discovered at the Premier No.2 mine in Cullinan , South Africa, on 26 January 1905. It was named after Thomas Cullinan , the owner of the mine. In April 1905, it was put on sale in London, but despite considerable interest, it was still unsold after two years. In 1907, the Transvaal Colony government bought
332-507: A Royal Navy ship carried an empty box across the North Sea , again throwing off potential thieves. Even the captain was unaware that his "precious" cargo was a decoy. On 10 February 1908, the rough stone was split in half by Joseph Asscher at his diamond-cutting factory in Amsterdam. At the time, technology had not yet evolved to guarantee the quality of modern standards, and cutting the diamond
498-681: A junior ministerial position he had requested. He worked beneath the Secretary of State for the Colonies , Victor Bruce, 9th Earl of Elgin , and took Edward Marsh as his secretary; Marsh remained his secretary for 25 years. Churchill's first task was helping to draft a constitution for the Transvaal ; and he helped oversee the formation of a government in the Orange River Colony . In dealing with southern Africa, he sought to ensure equality between
664-539: A subduction zone . Winston Churchill [REDACTED] Sir Winston Leonard Spencer Churchill (30 November 1874 – 24 January 1965) was a British statesman, military officer, and writer who was Prime Minister of the United Kingdom from 1940 to 1945 ( during the Second World War ) and again from 1951 to 1955. Apart from 1922 to 1924, he was a member of Parliament (MP) from 1900 to 1964 and represented
830-486: A Christie's auction. In May 2009, a 7.03-carat (1.406 g) blue diamond fetched the highest price per carat ever paid for a diamond when it was sold at auction for 10.5 million Swiss francs (6.97 million euros, or US$ 9.5 million at the time). That record was, however, beaten the same year: a 5-carat (1.0 g) vivid pink diamond was sold for US$ 10.8 million in Hong Kong on December 1, 2009. Clarity
996-511: A Liberal, Churchill attacked government policy and gained a reputation as a radical under the influences of John Morley and David Lloyd George . In December 1905, Balfour resigned as prime minister and King Edward VII invited the Liberal leader Henry Campbell-Bannerman to replace him. Hoping to secure a working majority , Campbell-Bannerman called a general election in January 1906, which
1162-487: A brooch. Cullinan IX is smallest of the principal diamonds to be obtained from the rough Cullinan. It is a pendeloque or stepped pear-cut stone, weighs 4.39 carats (0.878 g), and is set in a platinum ring known as the Cullinan ;IX Ring. Diamond#Gem-grade diamonds Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic . Diamond as
1328-453: A cigarette lighter, but house fires and blow torches are hot enough. Jewelers must be careful when molding the metal in a diamond ring. Diamond powder of an appropriate grain size (around 50 microns) burns with a shower of sparks after ignition from a flame. Consequently, pyrotechnic compositions based on synthetic diamond powder can be prepared. The resulting sparks are of the usual red-orange color, comparable to charcoal, but show
1494-727: A continuum with carbonatites , but the latter have too much oxygen for carbon to exist in a pure form. Instead, it is locked up in the mineral calcite ( Ca C O 3 ). All three of the diamond-bearing rocks (kimberlite, lamproite and lamprophyre) lack certain minerals ( melilite and kalsilite ) that are incompatible with diamond formation. In kimberlite , olivine is large and conspicuous, while lamproite has Ti- phlogopite and lamprophyre has biotite and amphibole . They are all derived from magma types that erupt rapidly from small amounts of melt, are rich in volatiles and magnesium oxide , and are less oxidizing than more common mantle melts such as basalt . These characteristics allow
1660-452: A diamond to fluoresce. Diamonds can fluoresce in a variety of colors including blue (most common), orange, yellow, white, green and very rarely red and purple. Although the causes are not well understood, variations in the atomic structure, such as the number of nitrogen atoms present are thought to contribute to the phenomenon. Diamonds can be identified by their high thermal conductivity (900– 2320 W·m ·K ). Their high refractive index
1826-425: A distinction between criminal and political prisoners , with rules for the latter being relaxed. There were educational innovations like the establishment of libraries, and a requirement to stage entertainments four times a year. The rules on solitary confinement were relaxed, and Churchill proposed abolition of automatic imprisonment of those who failed to pay fines. Imprisonment of people aged between 16 and 21
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#17328456439551992-557: A flat in London's Mayfair , using it as his base for six years. He stood again as a Conservative candidate at Oldham in the October 1900 general election , securing a narrow victory to become a Member of Parliament aged 25. In the same month, he published Ian Hamilton's March , a book about his South African experiences, which became the focus of a lecture tour in November through Britain, America and Canada. Members of Parliament were unpaid and
2158-563: A form of carbon is a tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of electricity, and insoluble in water. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure , but diamond is metastable and converts to it at a negligible rate under those conditions. Diamond has the highest hardness and thermal conductivity of any natural material, properties that are used in major industrial applications such as cutting and polishing tools. They are also
2324-475: A gemstone. Because it can only be scratched by other diamonds, it maintains its polish extremely well. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in engagement or wedding rings , which are often worn every day. The hardest natural diamonds mostly originate from the Copeton and Bingara fields located in
2490-590: A large majority, it established the principle of a minimum wage and the right to have meal breaks. In May 1909, he proposed the Labour Exchanges Bill to establish over 200 Labour Exchanges through which the unemployed would be assisted in finding employment. He promoted the idea of an unemployment insurance scheme, which would be part-funded by the state. To ensure funding for their reforms, Lloyd George and Churchill denounced Reginald McKenna 's policy of naval expansion, refusing to believe war with Germany
2656-598: A long platinum chain, which Elizabeth never wore in public, saying that "it gets in the soup". In the 1960s, two minor Cullinan diamonds owned by Louis Botha's heirs were analysed at the De Beers laboratory in Johannesburg and found to be completely free of nitrogen or any other impurities. Cullinans I and II were examined in the 1980s by gemologists at the Tower of London and both graded as colourless type IIa . Cullinan I, or
2822-475: A metallic fluid. The extreme conditions required for this to occur are present in the ice giants Neptune and Uranus . Both planets are made up of approximately 10 percent carbon and could hypothetically contain oceans of liquid carbon. Since large quantities of metallic fluid can affect the magnetic field, this could serve as an explanation as to why the geographic and magnetic poles of the two planets are unaligned. The most common crystal structure of diamond
2988-625: A mutual de-escalation, but this was refused. Churchill pushed for higher pay and greater recreational facilities for naval staff, more submarines, and a renewed focus on the Royal Naval Air Service , encouraging them to experiment with how aircraft could be used for military purposes. He coined the term " seaplane " and ordered 100 to be constructed. Some Liberals objected to his level of naval expenditure; in December 1913 he threatened to resign if his proposal for 4 new battleships in 1914–15
3154-511: A number of tiny flaws, scratches on the table facet, and a small chip at the girdle. Like Cullinan I, it is held in place by a yellow gold enclosure, which is screwed onto the crown. Cullinan III, or the Lesser Star of Africa, is pear-cut and weighs 94.4 carats (18.88 g). In 1911, Queen Mary , wife and queen consort of George V , had it set in the top cross pattée of a crown that she personally bought for her coronation. In 1912,
3320-403: A pale blue flame, and continues to burn after the source of heat is removed. By contrast, in air the combustion will cease as soon as the heat is removed because the oxygen is diluted with nitrogen. A clear, flawless, transparent diamond is completely converted to carbon dioxide; any impurities will be left as ash. Heat generated from cutting a diamond will not ignite the diamond, and neither will
3486-668: A preference for Protestantism over Roman Catholicism because he felt it "a step nearer Reason". Interested in parliamentary affairs, he declared himself "a Liberal in all but name", adding he could never endorse the Liberal Party 's support for Irish home rule . Instead, he allied himself to the Tory democracy wing of the Conservatives and on a visit home, gave his first speech for the party's Primrose League at Claverton Down . Mixing reformist and conservative perspectives, he supported
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#17328456439553652-514: A rainbow, or Newton's rings . Shortly after its discovery, Cullinan went on public display at the Standard Bank in Johannesburg , where it was seen by an estimated 8,000–9,000 visitors. In April 1905, the rough gem was deposited with Premier Mining Co.'s London sales agent, S. Neumann & Co . Due to its immense value, detectives were assigned to a steamboat that was rumoured to be carrying
3818-648: A reputation as a conciliator. He worked with Lloyd George to champion social reform . He promoted what he called a "network of State intervention and regulation" akin to that in Germany. Continuing Lloyd George's work, Churchill introduced the Mines Eight Hours Bill , which prohibited miners from working more than an eight-hour day . In 1909, he introduced the Trade Boards Bill , creating Trade Boards which could prosecute exploitative employers. Passing with
3984-614: A set of unpolished fragments. The Cullinan is estimated to have formed in Earth's mantle transition zone at a depth of 410–660 km (255–410 miles) and reached the surface 1.18 billion years ago. It was found 5.5 metres (18 ft) below the surface at Premier Mine in Cullinan , Transvaal Colony , by Frederick Wells, surface manager at the mine, on 26 January 1905. It was approximately 10.1 centimetres (4.0 in) long, 6.35 centimetres (2.50 in) wide, 5.9 centimetres (2.3 in) deep, and weighed 3,106 carats (621.2 grams). Newspapers called it
4150-586: A state funeral . One of the 20th century's most significant figures, Churchill remains popular in the UK and the rest of the Anglosphere . He is generally viewed as a victorious wartime leader who played an integral role in defending liberal democracy against the spread of fascism . He has sometimes been criticised for his imperialism and certain comments on race , in addition to some wartime decisions such as area bombing, but historians nevertheless rank Churchill as one of
4316-593: A state visit to the Netherlands , Queen Elizabeth II revealed that Cullinan III and IV are known in her family as "Granny's Chips". They visited the Asscher Diamond Company , where Cullinan had been cut 50 years earlier. It was the first time the Queen had worn the brooch publicly. During her visit, she unpinned the brooch and offered it for examination to Louis Asscher, nephew of Joseph Asscher, who split
4482-653: A strike in munitions factories along the Clyde and increased munitions production. In his October 1917 letter to his Cabinet colleagues, he penned the plan of attack for the next year, that would bring final victory to the Allies. He ended a second strike, in June 1918, by threatening to conscript strikers into the army. In the House of Commons, Churchill voted in support of the Representation of
4648-512: A total of five constituencies . Ideologically an adherent to economic liberalism and imperialism , he was for most of his career a member of the Conservative Party , which he led from 1940 to 1955. He was a member of the Liberal Party from 1904 to 1924. Of mixed English and American parentage, Churchill was born in Oxfordshire into the wealthy, aristocratic Spencer family . He joined
4814-463: A transition between graphite and diamond are well established theoretically and experimentally. The equilibrium pressure varies linearly with temperature, between 1.7 GPa at 0 K and 12 GPa at 5000 K (the diamond/graphite/liquid triple point ). However, the phases have a wide region about this line where they can coexist. At standard temperature and pressure , 20 °C (293 K) and 1 standard atmosphere (0.10 MPa),
4980-537: A very high refractive index and a relatively high optical dispersion . Most natural diamonds have ages between 1 billion and 3.5 billion years. Most were formed at depths between 150 and 250 kilometres (93 and 155 mi) in the Earth's mantle , although a few have come from as deep as 800 kilometres (500 mi). Under high pressure and temperature, carbon-containing fluids dissolved various minerals and replaced them with diamonds. Much more recently (hundreds to tens of million years ago), they were carried to
5146-467: A very linear trajectory which is explained by their high density. Diamond also reacts with fluorine gas above about 700 °C (1,292 °F). Diamond has a wide band gap of 5.5 eV corresponding to the deep ultraviolet wavelength of 225 nanometers. This means that pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities. The diamond crystal lattice
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5312-425: A volcanic rock. There are many theories for its origin, including formation in a star, but no consensus. Diamond is the hardest material on the qualitative Mohs scale . To conduct the quantitative Vickers hardness test , samples of materials are struck with a pyramid of standardized dimensions using a known force – a diamond crystal is used for the pyramid to permit a wide range of materials to be tested. From
5478-771: A war zone. In the autumn, he and friend Reggie Barnes , went to observe the Cuban War of Independence and became involved in skirmishes after joining Spanish troops attempting to suppress independence fighters. Churchill sent reports to the Daily Graphic in London. He proceeded to New York and wrote to his mother about "what an extraordinary people the Americans are!" With the Hussars, he went to Bombay in October 1896. Based in Bangalore , he
5644-449: Is 0.01% for nickel and even less for cobalt. Virtually any element can be introduced to diamond by ion implantation. Nitrogen is by far the most common impurity found in gem diamonds and is responsible for the yellow and brown color in diamonds. Boron is responsible for the blue color. Color in diamond has two additional sources: irradiation (usually by alpha particles), that causes the color in green diamonds, and plastic deformation of
5810-533: Is 6.5 cm (2.6 in) long and 2.4 cm (0.94 in) wide. Cullinan III has also been used as a pendant on the Coronation Necklace , where it occasionally replaced the 22.4-carat (4.48 g) Lahore Diamond. Cullinan IV, also referred to as a Lesser Star of Africa, is square-cut and weighs 63.6 carats (12.72 g). It was also set in the base of Queen Mary's Crown but was removed in 1914. On 25 March 1958, while she and Prince Philip were on
5976-415: Is a solid form of pure carbon with its atoms arranged in a crystal. Solid carbon comes in different forms known as allotropes depending on the type of chemical bond. The two most common allotropes of pure carbon are diamond and graphite . In graphite, the bonds are sp orbital hybrids and the atoms form in planes, with each bound to three nearest neighbors, 120 degrees apart. In diamond, they are sp and
6142-420: Is aided by isotopic dating and modeling of the geological history. Then surveyors must go to the area and collect samples, looking for kimberlite fragments or indicator minerals . The latter have compositions that reflect the conditions where diamonds form, such as extreme melt depletion or high pressures in eclogites . However, indicator minerals can be misleading; a better approach is geothermobarometry , where
6308-723: Is also indicative, but other materials have similar refractivity. Diamonds are extremely rare, with concentrations of at most parts per billion in source rock. Before the 20th century, most diamonds were found in alluvial deposits . Loose diamonds are also found along existing and ancient shorelines , where they tend to accumulate because of their size and density. Rarely, they have been found in glacial till (notably in Wisconsin and Indiana ), but these deposits are not of commercial quality. These types of deposit were derived from localized igneous intrusions through weathering and transport by wind or water . Most diamonds come from
6474-405: Is another mechanical property toughness , which is a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 50–65 MPa ·m . This value is good compared to other ceramic materials, but poor compared to most engineering materials such as engineering alloys, which typically exhibit toughness over 80 MPa·m . As with any material,
6640-414: Is called diamond cubic . It is formed of unit cells (see the figure) stacked together. Although there are 18 atoms in the figure, each corner atom is shared by eight unit cells and each atom in the center of a face is shared by two, so there are a total of eight atoms per unit cell. The length of each side of the unit cell is denoted by a and is 3.567 angstroms . The nearest neighbor distance in
6806-571: Is equivalent to £19 million in 2023. Due to a 60% tax on mining profits, the Treasury received some of its money back from the Premier Diamond Mining Company. The diamond was presented to the king at Sandringham House by Agent-General of the colony, Sir Richard Solomon , on 9 November 1907 – his 66th birthday – in the presence of a large party of guests, including the Queen of Sweden ,
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6972-402: Is exceptionally strong, and only atoms of nitrogen , boron , and hydrogen can be introduced into diamond during the growth at significant concentrations (up to atomic percents). Transition metals nickel and cobalt , which are commonly used for growth of synthetic diamond by high-pressure high-temperature techniques, have been detected in diamond as individual atoms; the maximum concentration
7138-419: Is formed of layers stacked in a repeating ABCABC ... pattern. Diamonds can also form an ABAB ... structure, which is known as hexagonal diamond or lonsdaleite , but this is far less common and is formed under different conditions from cubic carbon. Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles . As diamond's crystal structure has a cubic arrangement of
7304-412: Is higher for flawless, pure crystals oriented to the <111> direction (along the longest diagonal of the cubic diamond lattice). Therefore, whereas it might be possible to scratch some diamonds with other materials, such as boron nitride , the hardest diamonds can only be scratched by other diamonds and nanocrystalline diamond aggregates . The hardness of diamond contributes to its suitability as
7470-404: Is hybrid rock with a chaotic mixture of small minerals and rock fragments ( clasts ) up to the size of watermelons. They are a mixture of xenocrysts and xenoliths (minerals and rocks carried up from the lower crust and mantle), pieces of surface rock, altered minerals such as serpentine , and new minerals that crystallized during the eruption. The texture varies with depth. The composition forms
7636-647: Is in the form of micro/nanoscale wires or needles (~100–300 nanometers in diameter, micrometers long), they can be elastically stretched by as much as 9–10 percent tensile strain without failure, with a maximum local tensile stress of about 89–98 GPa , very close to the theoretical limit for this material. Other specialized applications also exist or are being developed, including use as semiconductors : some blue diamonds are natural semiconductors, in contrast to most diamonds, which are excellent electrical insulators . The conductivity and blue color originate from boron impurity. Boron substitutes for carbon atoms in
7802-477: Is one of the 4C's (color, clarity, cut and carat weight) that helps in identifying the quality of diamonds. The Gemological Institute of America (GIA) developed 11 clarity scales to decide the quality of a diamond for its sale value. The GIA clarity scale spans from Flawless (FL) to included (I) having internally flawless (IF), very, very slightly included (VVS), very slightly included (VS) and slightly included (SI) in between. Impurities in natural diamonds are due to
7968-797: Is partially oxidized. The oxidized surface can be reduced by heat treatment under hydrogen flow. That is to say, this heat treatment partially removes oxygen-containing functional groups. But diamonds (sp C) are unstable against high temperature (above about 400 °C (752 °F)) under atmospheric pressure. The structure gradually changes into sp C above this temperature. Thus, diamonds should be reduced below this temperature. At room temperature, diamonds do not react with any chemical reagents including strong acids and bases. In an atmosphere of pure oxygen, diamond has an ignition point that ranges from 690 °C (1,274 °F) to 840 °C (1,540 °F); smaller crystals tend to burn more easily. It increases in temperature from red to white heat and burns with
8134-576: Is pavé-set with a border of smaller diamonds. It can be suspended from the VIII brooch and can be used to suspend the VII pendant. It was often worn like this by Mary. In May 2023, the brooch was placed on the front of cross Queen Mary's Crown for the Coronation of Queen Camilla instead of the traditional and controversial Koh-i-Noor . Cullinan VI is marquise-cut and weighs 11.5 carats (2.30 g). It hangs from
8300-765: Is possible to treat regular diamonds under a combination of high pressure and high temperature to produce diamonds that are harder than the diamonds used in hardness gauges. Diamonds cut glass, but this does not positively identify a diamond because other materials, such as quartz, also lie above glass on the Mohs scale and can also cut it. Diamonds can scratch other diamonds, but this can result in damage to one or both stones. Hardness tests are infrequently used in practical gemology because of their potentially destructive nature. The extreme hardness and high value of diamond means that gems are typically polished slowly, using painstaking traditional techniques and greater attention to detail than
8466-454: Is the case with most other gemstones; these tend to result in extremely flat, highly polished facets with exceptionally sharp facet edges. Diamonds also possess an extremely high refractive index and fairly high dispersion. Taken together, these factors affect the overall appearance of a polished diamond and most diamantaires still rely upon skilled use of a loupe (magnifying glass) to identify diamonds "by eye". Somewhat related to hardness
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#17328456439558632-710: The 1945 general election , he became Leader of the Opposition . Amid the developing Cold War with the Soviet Union , he publicly warned of an " iron curtain " of Soviet influence in Europe and promoted European unity. Between his terms, he wrote several books recounting his experience during the war. He was awarded the Nobel Prize in Literature in 1953. He lost the 1950 election but was returned to office in 1951 . His second term
8798-539: The Agadir Crisis of April 1911, when there was a threat of war between France and Germany, Churchill suggested an alliance with France and Russia to safeguard the independence of Belgium, Denmark and the Netherlands to counter possible German expansionism. The Crisis had a profound effect on Churchill and he altered his views about the need for naval expansion. In October 1911, Asquith appointed Churchill First Lord of
8964-644: The Australian and New Zealand Army Corps (ANZAC), began its assault at Gallipoli . Both campaigns failed and Churchill was held by many MPs, particularly Conservatives, to be responsible. In May, Asquith agreed under parliamentary pressure to form an all-party coalition government , but the Conservatives' condition of entry was that Churchill must be removed from the Admiralty. Churchill pleaded his case with Asquith and Conservative leader Bonar Law but had to accept demotion. On 25 November 1915, Churchill resigned from
9130-760: The British Army in 1895 and saw action in British India , the Mahdist War and the Second Boer War , gaining fame as a war correspondent and writing books about his campaigns. Elected a Conservative MP in 1900, he defected to the Liberals in 1904. In H. H. Asquith 's Liberal government , Churchill was president of the Board of Trade and Home Secretary , championing prison reform and workers' social security. As First Lord of
9296-539: The Budget League , and warned that upper-class obstruction could anger working-class Britons and lead to class war. The government called the January 1910 general election , which resulted in a Liberal victory; Churchill retained his seat at Dundee. He proposed abolition of the House of Lords in a cabinet memo, suggesting it be succeeded by a unicameral system, or smaller second chamber that lacked an in-built advantage for
9462-569: The Delhi Durbar Tiara , worn the previous year by Mary instead of a crown at the Delhi Durbar , where her husband wore the Imperial Crown of India , was also adapted to take Cullinans III and IV. In 1914, Cullinan III was permanently replaced on the crown by a crystal model. Elizabeth II frequently wore Cullinan III in combination with Cullinan IV as a brooch. In total, the brooch
9628-731: The Earth's mantle , and most of this section discusses those diamonds. However, there are other sources. Some blocks of the crust, or terranes , have been buried deep enough as the crust thickened so they experienced ultra-high-pressure metamorphism . These have evenly distributed microdiamonds that show no sign of transport by magma. In addition, when meteorites strike the ground, the shock wave can produce high enough temperatures and pressures for microdiamonds and nanodiamonds to form. Impact-type microdiamonds can be used as an indicator of ancient impact craters. Popigai impact structure in Russia may have
9794-519: The Hughligans , but was critical of the Conservative government on various issues, especially increases in army funding. He believed additional military expenditure should go to the navy. This upset the Conservative front bench but was supported by Liberals, with whom he increasingly socialised, particularly Liberal Imperialists like H. H. Asquith . Churchill later wrote that he "drifted steadily to
9960-553: The New England area in New South Wales , Australia. These diamonds are generally small, perfect to semiperfect octahedra, and are used to polish other diamonds. Their hardness is associated with the crystal growth form, which is single-stage crystal growth. Most other diamonds show more evidence of multiple growth stages, which produce inclusions, flaws, and defect planes in the crystal lattice, all of which affect their hardness. It
10126-546: The Partition of Ireland . Concerning the possibility of partition, Churchill stated: "Whatever Ulster's right may be, she cannot stand in the way of the whole of the rest of Ireland. Half a province cannot impose a permanent veto on the nation. Half a province cannot obstruct forever the reconciliation between the British and Irish democracies". Speaking in the House of Commons on 16 February 1922, Churchill said: "What Irishmen all over
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#173284564395510292-505: The Queen of Spain , the Duke of Westminster and Lord Revelstoke . The king asked his colonial secretary, Lord Elgin , to announce that he accepted the gift "for myself and my successors" and that he would ensure "this great and unique diamond be kept and preserved among the historic jewels which form the heirlooms of the Crown". King Edward gave the larger diamond the name Great Star of Africa , while
10458-621: The Russian Civil War , but soon recognised the people's desire to bring them home. After the Soviets won the civil war, Churchill proposed a cordon sanitaire around the country. In the Irish War of Independence , he supported the use of the paramilitary Black and Tans to combat Irish revolutionaries. After British troops in Iraq clashed with Kurdish rebels, Churchill authorised two squadrons to
10624-667: The Siege of Ladysmith and take Pretoria. He was among the first British troops into both places. He and cousin, Charles Spencer-Churchill, 9th Duke of Marlborough , demanded and received the surrender of 52 Boer prison camp guards. Throughout the war, he publicly chastised anti-Boer prejudices, calling for them to be treated with "generosity and tolerance", and afterwards urged the British to be magnanimous in victory. In July, having resigned his lieutenancy, he returned to Britain. His Morning Post despatches had been published as London to Ladysmith via Pretoria and sold well. Churchill rented
10790-541: The Siege of Sidney Street ; three Latvian burglars had killed police officers and hidden in a house in the East End of London , surrounded by police. Churchill stood with the police though he did not direct their operation. After the house caught fire, he told the fire brigade not to proceed into the house because of the threat posed by the armed men. Afterwards, two of the burglars were found dead. Although he faced criticism for his decision, he said he "thought it better to let
10956-546: The Wawa belt of the Superior province in Canada and microdiamonds in the island arc of Japan are found in a type of rock called lamprophyre . Kimberlites can be found in narrow (1 to 4 meters) dikes and sills, and in pipes with diameters that range from about 75 m to 1.5 km. Fresh rock is dark bluish green to greenish gray, but after exposure rapidly turns brown and crumbles. It
11122-447: The greatest British prime ministers . Churchill was born on 30 November 1874 at his family's ancestral home, Blenheim Palace in Oxfordshire. On his father's side, he was a member of the aristocracy as a descendant of John Churchill, 1st Duke of Marlborough . His father, Lord Randolph Churchill , representing the Conservative Party , had been elected Member of Parliament (MP) for Woodstock in February 1874. His mother, Jennie ,
11288-436: The lithosphere . Such depths occur below cratons in mantle keels , the thickest part of the lithosphere. These regions have high enough pressure and temperature to allow diamonds to form and they are not convecting, so diamonds can be stored for billions of years until a kimberlite eruption samples them. Host rocks in a mantle keel include harzburgite and lherzolite , two type of peridotite . The most dominant rock type in
11454-415: The normal color range , and applies a grading scale from "D" (colorless) to "Z" (light yellow). Yellow diamonds of high color saturation or a different color, such as pink or blue, are called fancy colored diamonds and fall under a different grading scale. In 2008, the Wittelsbach Diamond , a 35.56-carat (7.112 g) blue diamond once belonging to the King of Spain, fetched over US$ 24 million at
11620-402: The upper mantle , peridotite is an igneous rock consisting mostly of the minerals olivine and pyroxene ; it is low in silica and high in magnesium . However, diamonds in peridotite rarely survive the trip to the surface. Another common source that does keep diamonds intact is eclogite , a metamorphic rock that typically forms from basalt as an oceanic plate plunges into the mantle at
11786-450: The "Cullinan Diamond", a reference to Sir Thomas Cullinan , who opened the mine in 1902. It was three times the size of the Excelsior Diamond , found in 1893 at Jagersfontein Mine , weighing 972 carats (194.4 g). Four of its eight surfaces were smooth, indicating that it once had been part of a much larger stone broken up by natural forces. It had a blue-white hue and contained a small pocket of air, which at certain angles produced
11952-545: The "disgusting butchery of the natives" by Europeans. With Campbell-Bannerman terminally ill, Asquith became prime minister in April 1908. He appointed Churchill as President of the Board of Trade . Aged 33, Churchill was the youngest Cabinet member since 1866. Newly appointed Cabinet ministers were legally obliged to seek re-election at a by-election. On 24 April, Churchill lost the Manchester North West by-election to
12118-750: The Admiralty during the First World War, he oversaw the Gallipoli campaign , but after it proved a disaster, was demoted to Chancellor of the Duchy of Lancaster . He resigned in November 1915 and joined the Royal Scots Fusiliers on the Western Front for six months. In 1917, he returned to government under David Lloyd George and served successively as Minister of Munitions , Secretary of State for War , Secretary of State for Air , and Secretary of State for
12284-471: The Admiralty , and he took up official residence at Admiralty House . He created a naval war staff and, over the next two and a half years, focused on naval preparation, visiting naval stations and dockyards, seeking to improve morale, and scrutinising German naval developments. After Germany passed its 1912 Naval Law to increase warship production, Churchill vowed that for every new German battleship, Britain would build two. He invited Germany to engage in
12450-570: The British and Boers. He announced a gradual phasing out of the use of Chinese indentured labourers in South Africa; he and the government decided a sudden ban would cause too much upset and might damage the colony's economy. He expressed concerns about the relations between European settlers and the black African population; after the Zulu launched their Bambatha Rebellion in Natal , Churchill complained about
12616-659: The Colonies , overseeing the Anglo-Irish Treaty and British foreign policy in the Middle East . After two years out of Parliament, he was Chancellor of the Exchequer in Stanley Baldwin 's Conservative government , returning sterling in 1925 to the gold standard , depressing the UK economy. Out of government during his so-called " wilderness years " in the 1930s, Churchill took the lead in calling for rearmament to counter
12782-508: The Conservative candidate by 429 votes. On 9 May, the Liberals stood him in the safe seat of Dundee , where he won comfortably . Churchill proposed marriage to Clementine Hozier ; they were married on 12 September 1908 at St Margaret's, Westminster and honeymooned in Baveno , Venice, and Veveří Castle in Moravia . They lived at 33 Eccleston Square , London, and their first daughter, Diana ,
12948-567: The Conservatives. In April, the Lords relented and the People's Budget passed. Churchill continued to campaign against the House of Lords and assisted passage of the Parliament Act 1911 which reduced and restricted its powers. In February 1910, Churchill was promoted to Home Secretary , giving him control over the police and prison services; he implemented a prison reform programme. Measures included
13114-588: The Crown Jewels, which belong to the King in right of the Crown. Asscher sold the minor stones to the South African government, which distributed them to Queen Mary; Louis Botha , then prime minister of South Africa; the diamond merchants Arthur and Alexander Levy, who supervised the cutting of Cullinan; and Jacob Romijn (later Romyn), who co-founded the first trade union in the diamond industry. Some were set by Mary into
13280-568: The Cullinan and Prime Minister Louis Botha presented it to Edward VII , the British king who reigned over the territory. It was then cut by Joseph Asscher & Co. in Amsterdam . Cullinan produced stones of various cuts and sizes, the largest of which is named Cullinan I, and named the Great Star of Africa by Edward VII, and at 530.4 carats (106.08 g) it is the largest clear cut diamond in
13446-650: The Dardanelles neutral zone, which was policed by the British army based in Chanak . Churchill and Lloyd George favoured military resistance to any Turkish advance but the majority Conservatives in the coalition government opposed it. A political debacle ensued which resulted in the Conservative withdrawal from the government, precipitating the November 1922 general election . Also in September, Churchill's fifth and last child, Mary ,
13612-737: The First World War began in August 1914. The navy transported 120,000 troops to France and began a blockade of Germany's North Sea ports. Churchill sent submarines to the Baltic Sea to assist the Russian Navy and sent the Marine Brigade to Ostend , forcing a reallocation of German troops. In September, Churchill assumed full responsibility for Britain's aerial defence. On 7 October, Clementine gave birth to their 3rd child, Sarah . In October, Churchill visited Antwerp to observe Belgian defences against
13778-482: The Great Star of Africa, is a pendeloque -cut brilliant weighing 530.2 carats (106.04 g) and has 74 facets. It is set at the top of the Sovereign's Sceptre with Cross , made in 1661, which had to be redesigned in 1910 to accommodate it. Cullinan I was surpassed as the world's largest cut diamond by the 545.67-carat (109.134 g) brown Golden Jubilee Diamond in 1992, but remains the largest colourless cut diamond in
13944-533: The Liberals won in a massive landslide. Churchill won the Manchester North West seat and his biography of his father was published; he received advance payment of £8,000. It was generally well received. The first biography of Churchill himself, written by the Liberal MacCallum Scott , was published. In the new government, Churchill became Under-Secretary of State for the Colonial Office ,
14110-539: The Malakand Field Force , which received positive reviews. He wrote his only work of fiction, Savrola , a Ruritanian romance . To keep occupied, Churchill embraced writing as what Roy Jenkins calls his "whole habit", especially through his career when he was out of office. Writing was his safeguard against recurring depression , which he referred to as his "black dog". Using London contacts, Churchill got attached to General Herbert Kitchener 's campaign in
14276-514: The Middle East, and was involved in the installations of Faisal I of Iraq and Abdullah I of Jordan . Churchill travelled to Mandatory Palestine where, as a supporter of Zionism , he refused an Arab Palestinian petition to prohibit Jewish migration. He did allow temporary restrictions following the Jaffa riots . In September 1922, the Chanak Crisis erupted as Turkish forces threatened to occupy
14442-506: The People Act 1918 , which gave some women the right to vote. In November 1918, four days after the Armistice , Churchill's fourth child, Marigold, was born. Lloyd George called a general election for 14 December 1918. During the campaign, Churchill called for nationalisation of the railways, a control on monopolies, tax reform, and the creation of a League of Nations to prevent wars. He
14608-506: The Rhine . Churchill was one of the few government figures who opposed harsh measures against Germany, and he cautioned against demobilising the German Army, warning they might be needed as a bulwark against Soviet Russia . He was outspoken against Vladimir Lenin 's Communist Party government in Russia. He initially supported using British troops to assist the anti-Communist White forces in
14774-732: The Sudan as a 21st Lancers subaltern while, working as a journalist for The Morning Post . After fighting in the Battle of Omdurman in September 1898, the 21st Lancers were stood down. In October, Churchill returned to England and began writing The River War , about the campaign published in 1899. He decided to leave the army as he was critical of Kitchener's actions, particularly the unmerciful treatment of enemy wounded and his desecration of Muhammad Ahmad 's tomb. On 2 December 1898, Churchill embarked for India to settle his military business and complete his resignation. He spent much time playing polo ,
14940-409: The animosity of party members would prevent him gaining a Cabinet position under a Conservative government. The Liberal Party was attracting growing support, and so his defection in 1904 may have been influenced by ambition. He increasingly voted with the Liberals. For example, he opposed an increase in military expenditure, supported a Liberal bill to restore legal rights to trade unions, and opposed
15106-485: The area, proposing they be equipped with "poison gas" to be used to "inflict punishment upon recalcitrant natives without inflicting grave injury upon them", although this was never implemented. He saw the occupation of Iraq as a drain on Britain and proposed, unsuccessfully, that the government should hand control back to Turkey. Churchill became Secretary of State for the Colonies in February 1921. The following month,
15272-539: The army form. After two unsuccessful attempts to gain admittance to the Royal Military College, Sandhurst , he succeeded. He was accepted as a cadet in the cavalry , starting in September 1893. His father died in January 1895. In February 1895, Churchill was commissioned as a second lieutenant in the 4th Queen's Own Hussars regiment of the British Army , based at Aldershot . Eager to witness military action, he used his mother's influence to get posted to
15438-462: The atoms form tetrahedra, with each bound to four nearest neighbors. Tetrahedra are rigid, the bonds are strong, and, of all known substances, diamond has the greatest number of atoms per unit volume, which is why it is both the hardest and the least compressible . It also has a high density, ranging from 3150 to 3530 kilograms per cubic metre (over three times the density of water) in natural diamonds and 3520 kg/m in pure diamond. In graphite,
15604-420: The atoms, they have many facets that belong to a cube , octahedron, rhombicosidodecahedron , tetrakis hexahedron , or disdyakis dodecahedron . The crystals can have rounded-off and unexpressive edges and can be elongated. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf , an opaque gum-like skin. Some diamonds contain opaque fibers. They are referred to as opaque if
15770-495: The besieging Germans and promised reinforcements. Soon afterwards, Antwerp fell to the Germans and Churchill was criticised in the press. He maintained that his actions had prolonged resistance and enabled the Allies to secure Calais and Dunkirk . In November, Asquith called a War Council including Churchill. Churchill set the development of the tank on the right track and financed its creation with Admiralty funds. Churchill
15936-469: The bill would "appeal to insular prejudice against foreigners, to racial prejudice against Jews, and to labour prejudice against competition" and expressed himself in favour of "the old tolerant and generous practice of free entry and asylum to which this country has so long adhered and from which it has so greatly gained". On 31 May 1904, he crossed the floor to sit as a member of the Liberal Party. As
16102-410: The bonds between nearest neighbors are even stronger, but the bonds between parallel adjacent planes are weak, so the planes easily slip past each other. Thus, graphite is much softer than diamond. However, the stronger bonds make graphite less flammable. Diamonds have been adopted for many uses because of the material's exceptional physical characteristics. It has the highest thermal conductivity and
16268-501: The brooch containing Cullinan VIII and forming part of the stomacher of the Delhi Durbar parure . Cullinan VI along with VIII can also be fitted together to make yet another brooch, surrounded by some 96 smaller diamonds. The design was created around the same time that the Cullinan V heart-shaped brooch was designed, both having a similar shape. Cullinan VII is also marquise-cut and weighs 8.8 carats (1.76 g). It
16434-507: The carbon source is more likely carbonate rocks and organic carbon in sediments, rather than coal. Diamonds are far from evenly distributed over the Earth. A rule of thumb known as Clifford's rule states that they are almost always found in kimberlites on the oldest part of cratons , the stable cores of continents with typical ages of 2.5 billion years or more. However, there are exceptions. The Argyle diamond mine in Australia ,
16600-436: The coloration, while pure or nearly pure diamonds are transparent and colorless. Most diamond impurities replace a carbon atom in the crystal lattice , known as a carbon flaw . The most common impurity, nitrogen, causes a slight to intense yellow coloration depending upon the type and concentration of nitrogen present. The Gemological Institute of America (GIA) classifies low saturation yellow and brown diamonds as diamonds in
16766-497: The compositions of minerals are analyzed as if they were in equilibrium with mantle minerals. Finding kimberlites requires persistence, and only a small fraction contain diamonds that are commercially viable. The only major discoveries since about 1980 have been in Canada. Since existing mines have lifetimes of as little as 25 years, there could be a shortage of new diamonds in the future. Diamonds are dated by analyzing inclusions using
16932-598: The decay of radioactive isotopes. Depending on the elemental abundances, one can look at the decay of rubidium to strontium , samarium to neodymium , uranium to lead , argon-40 to argon-39 , or rhenium to osmium . Those found in kimberlites have ages ranging from 1 to 3.5 billion years , and there can be multiple ages in the same kimberlite, indicating multiple episodes of diamond formation. The kimberlites themselves are much younger. Most of them have ages between tens of millions and 300 million years old, although there are some older exceptions (Argyle, Premier and Wawa). Thus,
17098-470: The diamond crystal lattice. Plastic deformation is the cause of color in some brown and perhaps pink and red diamonds. In order of increasing rarity, yellow diamond is followed by brown, colorless, then by blue, green, black, pink, orange, purple, and red. "Black", or carbonado , diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance. Colored diamonds contain impurities or structural defects that cause
17264-521: The diamond for Edward VII as "a token of the loyalty and attachment of the people of the Transvaal to His Majesty's throne and person". In August 1907, a vote was held in the Legislative Council on the Cullinan's fate, and a motion authorising the purchase was carried by 42 votes in favour to 19 against. Initially, Henry Campbell-Bannerman , then British Prime Minister, advised the king to decline
17430-501: The diamond lattice is 1.732 a /4 where a is the lattice constant, usually given in Angstrøms as a = 3.567 Å, which is 0.3567 nm. A diamond cubic lattice can be thought of as two interpenetrating face-centered cubic lattices with one displaced by 1 ⁄ 4 of the diagonal along a cubic cell, or as one lattice with two atoms associated with each lattice point. Viewed from a <1 1 1> crystallographic direction , it
17596-415: The diamond lattice, donating a hole into the valence band . Substantial conductivity is commonly observed in nominally undoped diamond grown by chemical vapor deposition . This conductivity is associated with hydrogen -related species adsorbed at the surface, and it can be removed by annealing or other surface treatments. Thin needles of diamond can be made to vary their electronic band gap from
17762-407: The diamonds' surface cannot be wet by water, but can be easily wet and stuck by oil. This property can be utilized to extract diamonds using oil when making synthetic diamonds. However, when diamond surfaces are chemically modified with certain ions, they are expected to become so hydrophilic that they can stabilize multiple layers of water ice at human body temperature . The surface of diamonds
17928-414: The fainting story, suggesting it was more likely Joseph would have celebrated, opening a bottle of champagne. When Joseph's nephew Louis heard the story, he exclaimed "No Asscher would ever faint over any operation on any diamond". Cullinan produced 9 major stones of 1,055.89 carats (211.178 g) in total, plus 96 minor brilliants and some unpolished fragments weighing 19.5 carats (3.90 g). All but
18094-449: The fibers grow from a clear substrate or fibrous if they occupy the entire crystal. Their colors range from yellow to green or gray, sometimes with cloud-like white to gray impurities. Their most common shape is cuboidal, but they can also form octahedra, dodecahedra, macles, or combined shapes. The structure is the result of numerous impurities with sizes between 1 and 5 microns. These diamonds probably formed in kimberlite magma and sampled
18260-468: The first exhibit of his paintings took place in Paris, with Churchill exhibiting under a pseudonym. In May, his mother died, followed in August by his daughter Marigold, from sepsis . Churchill was haunted by Marigold's death for the rest of his life. Churchill was involved in negotiations with Sinn Féin leaders and helped draft the Anglo-Irish Treaty . He was responsible for reducing the cost of occupying
18426-477: The first health and unemployment insurance legislation, the National Insurance Act 1911 , which Churchill had been instrumental in drafting. In May, Clementine gave birth to their second child, Randolph , named after Winston's father. In response to escalating civil strife in 1911, Churchill sent troops into Liverpool to quell protesting dockers and rallied against a national railway strike . During
18592-453: The government, although he remained an MP. Asquith rejected his request to be appointed Governor-General of British East Africa . Churchill decided to return to active service with the Army and was attached to the 2nd Grenadier Guards , on the Western Front . In January 1916, he was temporarily promoted to lieutenant-colonel and given command of the 6th Royal Scots Fusiliers . The battalion
18758-408: The hardness and transparency of diamond, are the reasons that diamond anvil cells are the main tool for high pressure experiments. These anvils have reached pressures of 600 GPa . Much higher pressures may be possible with nanocrystalline diamonds. Usually, attempting to deform bulk diamond crystal by tension or bending results in brittle fracture. However, when single crystalline diamond
18924-455: The highest sound velocity. It has low adhesion and friction, and its coefficient of thermal expansion is extremely low. Its optical transparency extends from the far infrared to the deep ultraviolet and it has high optical dispersion . It also has high electrical resistance. It is chemically inert, not reacting with most corrosive substances, and has excellent biological compatibility. The equilibrium pressure and temperature conditions for
19090-538: The house burn down rather than spend good British lives in rescuing those ferocious rascals". In March 1911, Churchill introduced the second reading of the Coal Mines Bill ; when implemented, it imposed stricter safety standards. He formulated the Shops Bill to improve working conditions of shop workers; it faced opposition from shop owners and only passed in a much emasculated form. In April, Lloyd George introduced
19256-499: The introduction of import tariffs. Arthur Balfour 's government announced protectionist legislation in October 1903. Two months later, incensed by Churchill's criticism of the government, the Oldham Conservative Association informed him it would not support his candidature at the next election. In May 1904, Churchill opposed the government's proposed Aliens Bill, designed to curb Jewish immigration. He stated that
19422-423: The kimberlites formed independently of the diamonds and served only to transport them to the surface. Kimberlites are also much younger than the cratons they have erupted through. The reason for the lack of older kimberlites is unknown, but it suggests there was some change in mantle chemistry or tectonics. No kimberlite has erupted in human history. Most gem-quality diamonds come from depths of 150–250 km in
19588-467: The largest producer of diamonds by weight in the world, is located in a mobile belt , also known as an orogenic belt , a weaker zone surrounding the central craton that has undergone compressional tectonics. Instead of kimberlite , the host rock is lamproite . Lamproites with diamonds that are not economically viable are also found in the United States, India, and Australia. In addition, diamonds in
19754-560: The left". He privately considered "the gradual creation by an evolutionary process of a Democratic or Progressive wing to the Conservative Party", or alternately a "Central Party" to unite the Conservatives and Liberals. By 1903, there was division between Churchill and the Conservatives, largely because he opposed their promotion of protectionism . As a free trader , he helped found the Free Food League . Churchill sensed that
19920-467: The macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond has a cleavage plane and is therefore more fragile in some orientations than others. Diamond cutters use this attribute to cleave some stones before faceting them. "Impact toughness" is one of the main indexes to measure the quality of synthetic industrial diamonds. Diamond has compressive yield strength of 130–140 GPa. This exceptionally high value, along with
20086-591: The melting point of diamond increases slowly with increasing pressure; but at pressures of hundreds of GPa, it decreases. At high pressures, silicon and germanium have a BC8 body-centered cubic crystal structure, and a similar structure is predicted for carbon at high pressures. At 0 K , the transition is predicted to occur at 1100 GPa . Results published in an article in the scientific journal Nature Physics in 2010 suggest that, at ultra-high pressures and temperatures (about 10 million atmospheres or 1 TPa and 50,000 °C), diamond melts into
20252-579: The melts to carry diamonds to the surface before they dissolve. Kimberlite pipes can be difficult to find. They weather quickly (within a few years after exposure) and tend to have lower topographic relief than surrounding rock. If they are visible in outcrops, the diamonds are never visible because they are so rare. In any case, kimberlites are often covered with vegetation, sediments, soils, or lakes. In modern searches, geophysical methods such as aeromagnetic surveys , electrical resistivity , and gravimetry , help identify promising regions to explore. This
20418-597: The mine owners and striking miners as "very unreasonable". The Times and other media outlets accused him of being soft on the rioters; in contrast, many in the Labour Party , which was linked to the trade unions, regarded him as too heavy-handed. Churchill incurred the long-term suspicion of the labour movement . Asquith called a general election in December 1910 , and the Liberals were re-elected with Churchill secure in Dundee. In January 1911, Churchill became involved in
20584-469: The normal 5.6 eV to near zero by selective mechanical deformation. High-purity diamond wafers 5 cm in diameter exhibit perfect resistance in one direction and perfect conductance in the other, creating the possibility of using them for quantum data storage. The material contains only 3 parts per million of nitrogen. The diamond was grown on a stepped substrate, which eliminated cracking. Diamonds are naturally lipophilic and hydrophobic , which means
20750-413: The offer, but he later decided to let Edward VII choose whether or not to accept the gift. Eventually, he was persuaded by Winston Churchill , then Colonial Under-Secretary. For his trouble, Churchill was sent a replica, which he enjoyed showing off to guests on a silver plate. The Transvaal Colony government bought the diamond on 17 October 1907 for £150,000, which adjusted for pound-sterling inflation
20916-400: The only ball sport in which he was ever interested. Having left the Hussars, he sailed from Bombay on 20 March 1899, determined to launch a career in politics. Churchill spoke at Conservative meetings and was selected as one of the party's two candidates for the June 1899 Oldham by-election . While campaigning, Churchill referred to himself as "a Conservative and a Tory Democrat". Although
21082-503: The political almanack. In an 1898 letter, he referred to his beliefs, saying: "I do not accept the Christian or any other form of religious belief". Churchill had been christened in the Church of England but underwent a virulently anti-Christian phase in his youth, and as an adult was an agnostic. In another letter to a cousin, he referred to religion as "a delicious narcotic" and expressed
21248-620: The presence of natural minerals and oxides. The clarity scale grades the diamond based on the color, size, location of impurity and quantity of clarity visible under 10x magnification. Inclusions in diamond can be extracted by optical methods. The process is to take pre-enhancement images, identifying the inclusion removal part and finally removing the diamond facets and noises. Between 25% and 35% of natural diamonds exhibit some degree of fluorescence when examined under invisible long-wave ultraviolet light or higher energy radiation sources such as X-rays and lasers. Incandescent lighting will not cause
21414-543: The promotion of secular, non-denominational education while opposing women's suffrage . Churchill volunteered to join Bindon Blood 's Malakand Field Force in its campaign against Mohmand rebels in the Swat Valley of north-west India. Blood accepted on condition he was assigned as a journalist, the beginning of Churchill's writing career. He returned to Bangalore in October 1897 and wrote his first book, The Story of
21580-478: The rank of major . Back in the House of Commons, Churchill spoke out on war issues, calling for conscription to be extended to the Irish, greater recognition of soldiers' bravery, and for the introduction of steel helmets. It was in November 1916 that he penned "The greater application of mechanical power to the prosecution of an offensive on land", but it fell on deaf ears. He was frustrated at being out of office, but
21746-476: The reason that diamond anvil cells can subject materials to pressures found deep in the Earth. Because the arrangement of atoms in diamond is extremely rigid, few types of impurity can contaminate it (two exceptions are boron and nitrogen ). Small numbers of defects or impurities (about one per million of lattice atoms) can color a diamond blue (boron), yellow (nitrogen), brown (defects), green (radiation exposure), purple, pink, orange, or red. Diamond also has
21912-453: The rioting. Churchill, learning that the troops were already travelling, allowed them to go as far as Swindon and Cardiff , but blocked their deployment; he was concerned their use lead to bloodshed. Instead he sent 270 London police, who were not equipped with firearms, to assist. As the riots continued, he offered the protesters an interview with the government's chief industrial arbitrator, which they accepted. Privately, Churchill regarded
22078-431: The rough diamond. Aged 84, he was deeply moved that the Queen had brought the diamonds with her, knowing how much it would mean to him seeing them again after so many years. Cullinan V is an 18.8-carat (3.76 g) heart-shaped diamond set in the centre of a platinum brooch that formed a part of the stomacher made for Queen Mary to wear at the Delhi Durbar in 1911. The brooch was designed to show off Cullinan V and
22244-524: The seats had been held by the Conservatives, the result was a narrow Liberal victory. Anticipating the outbreak of the Second Boer War between Britain and the Boer republics , Churchill sailed to South Africa as a journalist for the Morning Post . In October, he travelled to the conflict zone near Ladysmith , then besieged by Boer troops, before heading for Colenso . At the Battle of Chieveley , his train
22410-529: The size of the resulting indentation, a Vickers hardness value for the material can be determined. Diamond's great hardness relative to other materials has been known since antiquity, and is the source of its name. This does not mean that it is infinitely hard, indestructible, or unscratchable. Indeed, diamonds can be scratched by other diamonds and worn down over time even by softer materials, such as vinyl phonograph records . Diamond hardness depends on its purity, crystalline perfection, and orientation: hardness
22576-459: The smaller diamond was named the Smaller Star of Africa . The king chose Joseph Asscher & Co. of Amsterdam to cleave and polish the rough stone into brilliant gems of various cuts and sizes. Abraham Asscher collected it from the Colonial Office in London on 23 January 1908. He returned to the Netherlands by train and ferry with the diamond in his coat pocket. Meanwhile, to much fanfare,
22742-419: The stable phase of carbon is graphite, but diamond is metastable and its rate of conversion to graphite is negligible. However, at temperatures above about 4500 K , diamond rapidly converts to graphite. Rapid conversion of graphite to diamond requires pressures well above the equilibrium line: at 2000 K , a pressure of 35 GPa is needed. Above the graphite–diamond–liquid carbon triple point,
22908-682: The stone was valued at US$ 2.5 million (equivalent to US$ 60 million in 2023)– two and a half times the rough Cullinan's estimated value. Cullinan II, or the Second Star of Africa, is a cushion-cut brilliant with 66 facets weighing 317.4 carats (63.48 g) set in the front of the Imperial State Crown , below the Black Prince's Ruby (a large spinel ). It measures 4.54 cm × 4.08 cm × 2.42 cm (1.79 in × 1.61 in × 0.95 in). The diamond has
23074-568: The stone, and a parcel was ceremoniously locked in the captain's safe and guarded on the entire journey. It was a diversionary tactic – the stone on that ship was fake, meant to attract those who would be interested in stealing it. Cullinan was sent to the United Kingdom in a plain box via registered post. On arriving in London, it was conveyed to Buckingham Palace for inspection by King Edward VII . Although it drew considerable interest from potential buyers, Cullinan went unsold for two years. Transvaal Prime Minister Louis Botha suggested buying
23240-524: The surface in volcanic eruptions and deposited in igneous rocks known as kimberlites and lamproites . Synthetic diamonds can be grown from high-purity carbon under high pressures and temperatures or from hydrocarbon gases by chemical vapor deposition (CVD). Imitation diamonds can also be made out of materials such as cubic zirconia and silicon carbide . Natural, synthetic, and imitation diamonds are most commonly distinguished using optical techniques or thermal conductivity measurements. Diamond
23406-451: The task. "The tale is told of Joseph Asscher, the greatest cleaver of the day," wrote Matthew Hart in his book Diamond: A Journey to the Heart of an Obsession (2002), "that when he prepared to cleave the largest diamond ever known … he had a doctor and nurse standing by and when he finally struck the diamond … he fainted dead away". Lord Ian Balfour, in his book Famous Diamonds (2009), dispels
23572-549: The threat of militarism in Nazi Germany . At the outbreak of the Second World War he was re-appointed First Lord of the Admiralty. In May 1940, he became prime minister, succeeding Neville Chamberlain . Churchill formed a national government and oversaw British involvement in the Allied war effort against the Axis powers , resulting in victory in 1945 . After the Conservatives' defeat in
23738-458: The tour was a financial necessity. In America, Churchill met Mark Twain , President McKinley and Vice President Theodore Roosevelt , who he did not get on with. In spring 1901, he gave lectures in Paris, Madrid and Gibraltar. In February 1901, Churchill took his seat in the House of Commons , where his maiden speech gained widespread coverage. He associated with a group of Conservatives known as
23904-614: The two largest stones – Cullinans I and II – remained in Amsterdam by arrangement as the fee for Asscher's services, until the South African government bought them (except Cullinan VI, which Edward VII had purchased and given to his wife Queen Alexandra in 1907), and the High Commissioner for Southern Africa presented them to Queen Mary on 28 June 1910. Mary also inherited Cullinan VI from Alexandra, and she left all her Cullinan diamonds to her granddaughter Elizabeth II in 1953. Cullinans I and II are part of
24070-454: The volatiles. Diamonds can also form polycrystalline aggregates. There have been attempts to classify them into groups with names such as boart , ballas , stewartite, and framesite, but there is no widely accepted set of criteria. Carbonado, a type in which the diamond grains were sintered (fused without melting by the application of heat and pressure), is black in color and tougher than single crystal diamond. It has never been observed in
24236-545: The whole of the twenty years I had lived". Churchill began boarding school at St George's in Ascot, Berkshire , aged 7, but he was not academic and his behaviour was poor. In 1884, he transferred to Brunswick School in Hove , where his academic performance improved. In April 1888, aged 13, he passed the entrance exam for Harrow School . His father wanted him to prepare for a military career, so his last three years at Harrow were in
24402-462: The world most desire is not hostility against this country, but the unity of their own". Following a Cabinet decision, he boosted the naval presence in Ireland to deal with any Unionist uprising. Seeking a compromise, Churchill suggested Ireland remain part of a federal UK, but this angered Liberals and Irish nationalists. As First Lord, Churchill was tasked with overseeing Britain's naval effort when
24568-430: The world's largest diamond deposit, estimated at trillions of carats, and formed by an asteroid impact. A common misconception is that diamonds form from highly compressed coal . Coal is formed from buried prehistoric plants, and most diamonds that have been dated are far older than the first land plants . It is possible that diamonds can form from coal in subduction zones , but diamonds formed in this way are rare, and
24734-407: The world. In terms of clarity, it has a few tiny cleavages and a small patch of graining. The 5.89 cm × 4.54 cm × 2.77 cm (2.32 in × 1.79 in × 1.09 in) diamond is fitted with loops and can be taken out of its setting to be worn as a pendant suspended from Cullinan II to make a brooch . Queen Mary, wife of George V, often wore it like this. In 1908,
24900-574: The world. The stone is mounted in the head of the Sovereign's Sceptre with Cross . The second-largest is Cullinan II or the Second Star of Africa, weighing 317.4 carats (63.48 g), mounted in the Imperial State Crown . Both are part of the Crown Jewels of the United Kingdom . Seven other major diamonds, weighing a total of 208.29 carats (41.66 g), were privately owned by Elizabeth II , who inherited them from her grandmother, Queen Mary , in 1953. The Queen also owned minor brilliants and
25066-531: Was a committed opponent, and targeted his meetings for protest. In November 1910, the suffragist Hugh Franklin attacked Churchill with a whip; Franklin was imprisoned for six weeks. In November 1910, Churchill had to deal with the Tonypandy riots , in which coal miners in the Rhondda Valley violently protested against working conditions. The Chief Constable of Glamorgan requested troops to help police quell
25232-555: Was a daughter of Leonard Jerome , an American businessman. In 1876, Churchill's paternal grandfather, John Spencer-Churchill, 7th Duke of Marlborough , was appointed Viceroy of Ireland . Randolph became his private secretary and the family relocated to Dublin . Winston's brother, Jack , was born there in 1880. For much of the 1880s, Randolph and Jennie were effectively estranged, and the brothers cared for by their nanny, Elizabeth Everest . When she died in 1895, Churchill wrote "she had been my dearest and most intimate friend during
25398-522: Was abolished except for the most serious offences. Churchill reduced ( "commuted" ) 21 of the 43 death ( "capital" ) sentences passed while he was Home Secretary. A major domestic issue was women's suffrage. Churchill supported giving women the vote, but would only back a bill to that effect if it had majority support from the (male) electorate. His proposed solution was a referendum, but this found no favour with Asquith and women's suffrage remained unresolved until 1918. Many suffragettes believed Churchill
25564-473: Was born in 1909. The success of their marriage was important to Churchill's career as Clementine's unbroken affection provided him with a secure and happy background. One of Churchill's first tasks as a minister was to arbitrate in an industrial dispute among ship-workers and employers, on the River Tyne . He afterwards established a Standing Court of Arbitration to deal with industrial disputes, establishing
25730-533: Was born, and in the same month he purchased Chartwell , in Kent, which became his family home. In October 1922, he underwent an appendectomy . While he was in hospital, Lloyd George's coalition was dissolved. In the general election, Churchill lost his Dundee seat to Edwin Scrymgeour , a prohibitionist candidate. Later, he wrote that he was "without an office, without a seat, without a party, and without an appendix". He
25896-662: Was derailed by Boer artillery shelling, he was captured as a prisoner of war (POW) and interned in a POW camp in Pretoria . In December, Churchill escaped and evaded his captors by stowing aboard freight trains and hiding in a mine. He made it to safety in Portuguese East Africa . His escape attracted much publicity. In January 1900, he briefly rejoined the army as a lieutenant in the South African Light Horse regiment, joining Redvers Buller 's fight to relieve
26062-483: Was difficult and risky. After weeks of planning, an incision 0.5 inches (13 mm) deep was made to enable Asscher to cleave the diamond in one blow. Making the incision alone took four days, and a steel knife broke on the first attempt, but a second knife was fitted into the groove and split the stone cleanly in two along one of four possible cleavage planes. In all, splitting and cutting the diamond took eight months, with three people working 14 hours per day to complete
26228-549: Was in India for 19 months, visiting Calcutta and joining expeditions to Hyderabad and the North West Frontier . In India, Churchill began a self-education project, reading widely including Plato , Edward Gibbon , Charles Darwin and Thomas Babington Macaulay . The books were sent by his mother, with whom he shared frequent correspondence. To learn about politics, he asked her to send him copies of The Annual Register ,
26394-420: Was inevitable. As Chancellor, Lloyd George presented his " People's Budget " on 29 April 1909, calling it a war budget to eliminate poverty. With Churchill as his closest ally, Lloyd George proposed unprecedented taxes on the rich to fund Liberal welfare programmes. The budget was vetoed by the Conservative peers who dominated the House of Lords . His social reforms under threat, Churchill became president of
26560-741: Was interested in the Middle Eastern theatre , and wanted to relieve pressure on the Russians in the Caucasus by staging attacks against Turkey in the Dardanelles . He hoped that the British could even seize Constantinople . Approval was given and, in March 1915, an Anglo-French task force attempted a naval bombardment of Turkish defences. In April, the Mediterranean Expeditionary Force , including
26726-507: Was moved to a sector of the Belgian Front near Ploegsteert . For three months, they faced continual shelling, though no German offensive. Churchill narrowly escaped death when, during a visit by his cousin Marlborough , a large piece of shrapnel fell between them. In May, the 6th Royal Scots Fusiliers were merged into the 15th Division. Churchill did not request a new command, instead securing permission to leave active service. His temporary promotion ended on 16 May 1916, when he returned to
26892-455: Was originally given by Edward VII to his wife and consort Queen Alexandra . After his death she gave the jewel to Queen Mary, who had it set as a pendant hanging from the diamond-and-emerald Delhi Durbar necklace, part of the parure. Cullinan VIII is an oblong-cut diamond weighing 6.8 carats (1.36 g). It is set in the centre of a brooch forming part of the stomacher of the Delhi Durbar parure. Together with Cullinan VI it forms
27058-401: Was preoccupied with foreign affairs, especially Anglo-American relations and preservation of what remained of the British Empire , with India no longer a part of it. Domestically, his government's priority was their extensive housebuilding programme, in which they were successful. In declining health, Churchill resigned in 1955, remaining an MP until 1964 . Upon his death in 1965, he was given
27224-402: Was rejected. In June 1914, he convinced the House of Commons to authorise the government purchase of a 51% share in the profits of the Anglo-Persian Oil Company , to secure oil access for the navy. The central issue in Britain was Irish Home Rule and, in 1912, Asquith's government introduced the Home Rule Bill . Churchill supported it and urged Ulster Unionists to accept it as he opposed
27390-458: Was repeatedly blamed for the Gallipoli disaster by the pro-Conservative press. Churchill argued his case before the Dardanelles Commission , whose report placed no blame on him personally for the campaign's failure. In October 1916, Asquith resigned as prime minister and was succeeded by Lloyd George who, in May 1917, sent Churchill to inspect the French war effort. In July, Churchill was appointed Minister of Munitions . He negotiated an end to
27556-407: Was returned as MP for Dundee and, though the Conservatives won a majority, Lloyd George was retained as prime minister. In January 1919, Lloyd George moved Churchill to the War Office as both Secretary of State for War and Secretary of State for Air . Churchill was responsible for demobilising the army, though he convinced Lloyd George to keep a million men conscripted for the British Army of
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