The Crown of Princess Blanche , also called the Palatine Crown or Bohemian Crown , is the oldest surviving royal crown known to have been in England , and probably dates to 1370–80.
113-460: It is made of gold with diamonds , balas rubies , emeralds , sapphires , enamel and pearls . Its height and diameter are both 18 centimetres (7.1 in). The crown has been a property of the House of Wittelsbach since 1402, when it came with Princess Blanche of England , daughter of King Henry IV of England , on her marriage to Louis III, Elector Palatine . After the junior Bavarian branch of
226-403: A calefactory that was heated by lighting a fire in a vaulted chamber underneath the calefactory. Smoke was funneled outside and the heat rose into the calefactory through the 20 holes in its floor. It was the only heated room in the monastery. Attached to the center of the eastern side of the cloister is the chapter house , where monks could break their oaths of silence. Three pillars hold up
339-544: A subduction zone . Maulbronn Monastery Maulbronn Monastery (German: Kloster Maulbronn ) is a former Cistercian abbey and ecclesiastical state in the Holy Roman Empire located at Maulbronn , Baden-Württemberg. The monastery complex, one of the best-preserved in Europe, was named a UNESCO World Heritage Site in 1993. The monastery was founded in 1147 and experienced rapid economic and political growth in
452-486: 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
565-587: A French or French-trained goldsmith working in Prague . Venice has also been suggested as the crown's place of origin. The crown came to the Palatine line of the House of Wittelsbach as dowry of Blanche of England , daughter of King Henry IV of England . After his accession to the English throne, Henry wanted to make important alliances in order to maintain and legitimize his rule. One ally whose support he hoped to gain
678-453: 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
791-727: 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
904-452: 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
1017-563: 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
1130-475: 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
1243-627: A large image of Christ crucified , carved around 1473 from a single block of stone. At the end of the lay brother's section is the organ, installed by Gerhard Grenzing [ de ] in 2013. In the choir is a Madonna and Child , the Maulbronner Madonna , crafted somewhere between 1307 and 1317. In the chancel below is the abbot's chair and a set of choir stalls for seat 92 monks. They were carved around 1450 by an unknown master, possibly Hans Multscher , who covered them in biblical scenes and mythical creatures. The frescoes within
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#17328587609801356-546: A library. After Maulbronn's acquisition by the Dukes of Württemberg, the hospital was renovated as the abbot's residence and gained its name from the abbot's title, "Ephorus". In 1588, Duke Louis III built a lustschloss over the cellar of an earlier building, likely the abbot's residence. During the existence of the Oberamt Maulbronn [ de ] , Louis III's lustschloss was its administrative office. Nearby are
1469-437: A lily. The stems and lilies alternate in size and height. They are heavily jewelled versions of the fleur de lys (lily flower) that was popular for medieval crowns. In the middle of the hexagons, which have enamelled white flowers overlaid onto a translucent blue or red background, is a pale blue sapphire, 11 of which are oval and 1 is hexagonal. Each point is decorated with alternating rubies and clusters of four pearls that have
1582-475: 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
1695-518: A new administrative district. A Protestant Valentin Vannius [ de ] , a former monk at Maulbronn, was appointed abbot and thus the head of Maulbronn's seminary in 1558. Two Lutheran colloquys were held at Maulbronn, in 1564 and 1576. The Thirty Years' War forced the monastery school to close until 1656. During the Nine Years War , Maulbronn was part of the defensive network of
1808-403: 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
1921-637: A party of 12 monks . They arrived in 1138, but found Eckenweiher to be lacking in water and pasture space. In 1147, the Eckenweiher monks were moved to a new site near the source of the Salzach river by the Bishop of Speyer , Günther von Henneberg [ de ] . This site, Mulenbrunnen, about 8 kilometers (5.0 mi) from Eckenweiher, was ideal for the Cistercians. Located in the hilly Stromberg region, it
2034-696: A reading of the Bible. This building was possibly also built by the Master of the Paradise, as evidenced by the Early Gothic elements of its interior. The ribbing of the vaults was painted red in the 16th century. The kitchen that supplied the two refectories is located between them, but arranged such to keep smoke and odors away from the rest of the monastery. Although the Cistercian Order banned heated rooms, Maulbronn has
2147-422: A small diamond at the centre. In addition to diamonds, pearls, and sapphires, the lilies are also decorated with emeralds. Some of the original pearls may have been replaced when the crown was restored in 1925. The lily stems are detachable, and it is possible to fold the crown's base so that it can be transported more easily. Each rosette is numbered 1–12 to make sure the lilies are re-attached correctly. The crown
2260-470: A sophisticated water management system. By draining the wetlands around the monastery and digging a series of canals, the monks created some 20 ponds and lakes. A local stream, the Salzach, was diverted to flow under the monastery to form its sewerage . The water levels in these lakes could be controlled, allowing Maulbronn's monks to power their mill , but also to raise fish and eels. In one of these ponds,
2373-538: A tower gate, today houses the Maulbronn town hall and other administrative offices, and a police station. The monastery itself contains an Evangelical seminary and a boarding school. In 1138, a free knight named Walter von Lomersheim donated an estate at Eckenweiher (now Mühlacker ) to the Cistercian Order for the establishment of a new monastery. The donation was received by Neubourg Abbey , which dispatched
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#17328587609802486-463: 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),
2599-585: 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
2712-467: 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
2825-425: 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
2938-441: Is "Learn", dedicated to the monastery's use as a Protestant seminary and with a focus on alumni of the seminary such as Johannes Kepler , Friedrich Hölderlin , and Herman Hesse . Finally, "Write" showcases the works of the monks at Maulbronn and a library spanning 800 years and 50 writers. The abbey's cellarium houses a lapidarium and exhibit detailing the construction methods used at Maulbronn. The ancient quarters now house
3051-449: 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
3164-443: Is 18 centimetres (7.1 in) in both height and diameter. The nuptial crown is first documented in the inventory of King Richard II of England as having 12 fleurons, but a rosette was missing. At the time, it was decorated with 91 pearls, 63 balas rubies , 47 sapphires, 33 diamonds, and 5 emeralds. An additional 7 pearls and 1 emerald had been taken off the fleurons. The crown weighed 5 marks 7 oz, or just under 1 kilogram, and
3277-415: 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
3390-420: 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
3503-723: 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
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3616-405: 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,
3729-414: 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
3842-402: 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
3955-419: 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
4068-412: 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
4181-404: 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
4294-647: 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
4407-477: 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
4520-797: 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
4633-765: 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
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4746-454: 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
4859-522: Is the workplace and residence of the monastery's chief baker. Finally, there are three half-timber buildings. The first is the Speisemeisterei, next to the sawmill, and the third is the Bursarium, built in 1742 as the cemetery office but used as a police station and notary as of 2019. The middle building, built in 1550, was a servant's quarters. At the center of the monastery complex is the abbey, where
4972-521: The Aalkistensee , the monks could raise up to 5000 carp. Much of the system remains in use and is part of Maulbronn's UNESCO inscription. The water system has been under study by Baden-Württemberg's Office for the Preservation of Monuments [ de ] since 1989. The cooperage , near the gatehouse, is the visitor center. On the ground floor is a diorama of the monastery complex and on
5085-731: 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
5198-526: The Eppingen lines , built from 1695 to 1697 by Louis William, Margrave of Baden-Baden . In the later years of the 17th century, Duke Louis III tasked his court architect, Georg Beer [ de ] , with renovating the monastery for the seminary. In that time, Louis III had a hunting lodge built on the monastery grounds, likely designed by Beer. Maulbronn Monastery was finally secularized by King Frederick I in 1806. Efforts to preserve and restore
5311-639: The Füllmenbacher [ de ] and Elfinger farmsteads in 1152 and 1153 respectively, and then established Schöntal Abbey in 1157. Maulbronn has exempted from paying tithes and was made an Imperial Abbey by Emperor Frederick I in a 1156 that listed Maulbronn's possessions as comprising eleven farmsteads, portions of eight villages, and numerous vineyards. The monastery's holdings were again confirmed by Pope Alexander III in 1177; by then, Maulbronn owned seventeen farmsteads. The 13th and 14th centuries were periods of strife for Maulbronn, though in
5424-578: The House of Enzberg [ de ] became Maulbronn's patrons and vögte , or protectors. There was persistent conflict with the Enzbergs, however, and one dispute in 1270 even saw the monastery temporarily suppressed. Emperor Charles IV transferred the vogtei of Maulbronn to the Electoral Palatinate in 1372, but this act drew the monastery into the power struggle between the Palatinate and
5537-553: 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
5650-546: 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
5763-436: 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
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#17328587609805876-523: 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
5989-402: 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
6102-614: The 12th century, but then hardship in the late 13th century and the 14th century. Prosperity returned in the 15th century and lasted until Maulbronn was annexed by the Duchy of Württemberg in 1504. Over the 16th century, the Cistercian monastery was dissolved and replaced with a Protestant seminary . It also became the seat of an important administrative district of the Duchy and later Kingdom of Württemberg . The complex, surrounded by turreted walls and
6215-461: The 1555 Peace of Augsburg restored religious peace in the Empire, however, Christoph, Duke of Württemberg was able to fully reform the Duchy. In 1556, Christoph reformed the monasteries. Following a program created by one of his advisors, Johannes Brenz , he established Protestant seminaries in thirteen of Württemberg's monasteries. Maulbronn's holdings were absorbed into the Duchy and organized into
6328-522: The Palatinate. Maximilian I additionally forbade any further fortification of the abbey, and ordered its existing works demolished. In 1504, during the War of the Succession of Landshut , Ulrich, Duke of Württemberg took Maulbronn after a seven-day siege. Ulrich subsequently had Maulbronn's vogtei transferred to him, effectively annexing the monastery and its territories into the Duchy of Württemberg . In 1525,
6441-462: 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,
6554-420: 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
6667-619: The backing of both Bishop Henneberg, a supporter of the Cistericans and the Hohenstaufen , who were at the time the rulers of the Holy Roman Empire . In 1148, Bishop Henneberg waived Maulbronn's obligation to pay levies for the large amount of forest its monks had to clear and Pope Eugene III granted the monastery the right of patronage . Meanwhile, Maulbronn aggressively pursued the acquisition of new territory. In 1151, Maulbronn established Bronnbach Abbey [ de ] , then acquired
6780-432: The base bowl is original. The five Gothic windows were added from 1340 to 1350 and the half-timber structure above the lavatorium was built around 1611 in a style similar to that of Heinrich Schickhardt [ de ] . The vaults of the lavatorium were painted with a depiction of Maulbronn's founding myth. Across from the fountain house is the monks' refectory, where the full brothers ate their meals and listened to
6893-410: 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
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#17328587609807006-507: 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 ,
7119-513: The church depict the Adoration of the Magi , the entrance of Maulbronn's founder Walter von Lomersheim into the monastery as a lay brother. Also present are the coats of arms of nobles who donated to the monastery's construction. The donor chapels, built within rather than outside the church, and vaulted Gothic roof, replacing the original flat and timber roof, were added when the church was renovated in
7232-436: 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
7345-497: 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
7458-403: The convents of Mariental [ de ] , Rechtenshofen [ de ] , Lichtenstern [ de ] , Heilsbruck [ de ] , and Koenigsbruck . The number of monks at Maulbronn peaked at one hundred thirty-five in the 1460s and only dipped below one hundred again at the end of the century. In 1492, Emperor Maximilian I withdrew the vogtei of Maulbronn from
7571-598: 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,
7684-470: 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
7797-501: 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
7910-415: 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
8023-407: 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
8136-503: The eastern side of the cloister goes to a Late Gothic connecting building, built by lay brother Conrad von Schmie, leading to the monastery hospital, the Ephorat. The connecting building is decorated with a mural depicting Benedict of Nursia and Bernard of Clairvaux kneeling before the Virgin Mary . From the symbolism, it is thought this space was used as a Marian chapel, a scriptorium , or
8249-451: The expanding County of Württemberg . Prosperity returned to Maulbronn in the 15th century. Its abbots demonstrated the monastery's wealth in 1450, when it made easily the largest contribution of any Cistercian abbey that year to Cîteaux Abbey , the order's seat. In 1464, Maulbronn assumed the debts of Pairis Abbey in Alsace and incorporated it as a priory. Maulbronn also came to control
8362-449: 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
8475-408: 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
8588-455: 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
8701-518: The house became extinct in the male line in 1777, the senior Palatine branch replaced the former as the country's rulers. Today, the crown is displayed in the treasury of the Munich Residenz , where it has been kept since 1782. It has been described as "one of the finest achievements of the Gothic goldsmith". The crown is made up of 12 hexagonal rosettes on the base each supporting a gold stem topped by
8814-423: 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
8927-467: 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
9040-562: The late 15th century. The altar , likely of South German make, depicts the Passion of Jesus and was once gilded and painted. Those pieces of the set that remain have since 1978 sat on a sandstone slab in the chapel. The church's narthex is Germany's oldest example of Gothic architecture – the "Paradise", built around 1220. The portal into the lay brothers' church contain the oldest datable doors in Germany, fashioned from fir wood in 1178. The door
9153-424: The lay refectory on the ground floor. The groin vaults are supported by seven slender double-column pillars installed in 1869. Opposite the corridor to the cloister from the lay refectory is the cellarium , now a display of stonemasonry paraphernalia. On the north side of the cloister is the lavatorium , where monks washed before meals and for ablution . The majority of the fountain within dates to 1878; only
9266-467: 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
9379-508: The medieval character of the monastery complex began in 1840. The monastery school was taken over by the Nazi Party in 1941. It was reopened in 1945–46. The Paradise and the fountain in the lavatorium appear on the 2013 German Bundesländer series 2 euro coin. 30 million of these coins were minted in Berlin , Munich, Stuttgart , Karlsruhe , and Hamburg . An average of 235,000 persons visit
9492-591: 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
9605-579: 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
9718-488: The monastery each year as of 2019. The architectural history of the Maulbronn Monastery complex is still not fully understood. The monastery was constructed in the 12th century in a Romanesque style , though little of the 12th century work – the portal and its original doors – has been preserved. The specific style used, called the " Hirsau style", was native to Swabia and is characterized by uniform pillars and
9831-614: The monastery was occupied by peasants participating in the German Peasants' War in 1525 and the monks were expelled. Duke Ulrich adopted the Lutheran faith in 1534, and subsequently ordered the dissolution of all monasteries within Württemberg's territories, and seized their properties. Maulbronn was the sole exception to this order, as it was to host monks expelled from other monasteries. In 1536, Maulbronn's abbot relocated to Pairis and
9944-401: The monks and lay brothers lived and prayed. The monastery had strict divisions between the two groups. This was so even in the church, which is divided into sections for the former and the latter by a choir wall. There are two ciboriums , decorated with toads, lizards, and skulls and a number of medieval works on both sides of the choir wall. In front of this wall on the lay brother's side is
10057-507: The monks' refectory . The Late Gothic came to Maulbronn from the late 13th century to the mid-14th century, and again in the German Romantic era of the late 19th century. There is a very limited amount of Renaissance architecture at Maulbronn, represented primarily by Duke Ludwig's hunting manor. The monastery as a whole survives due mostly to the Dukes of Württemberg . The monastery
10170-556: The next year began legal action to reclaim Maulbronn. The Imperial Diet of the Holy Roman Empire decided in the Cistercians' favor at the 1548 Augsburg Interim , which followed the defeat of Ulrich and the other Protestant princes in the Schmalkaldic War . Ulrich was ordered to restore the Württemberg's monasteries and convents and, though he tried to delay their restoration, the Cistercians returned to Maulbronn in 1548. After
10283-469: 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
10396-620: 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
10509-476: 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
10622-576: The rectangular frames around the Romanesque arches. Near the end of the 12th century the architecture of the Cistercians became influenced by Gothic architecture , and the order began disseminating it from northeastern France. From 1210 to 1220, an anonymous architect trained in Paris erected the first example of Gothic architecture in Germany at Maulbronn's narthex , the southern portion of its cloister , and
10735-462: The remains of a Romanesque gate demolished in 1813. A lead pipe found here suggests that there used to be a well nearby. East of the gate is the Fruchtkasten, today a concert hall. It was built in the 13th century and then totally rebuilt and enlarged in 1580 for the storage and use of wine-making equipment. To the north of the gate is the monastery's administrative and economic buildings. Along
10848-403: The residence of the monk responsible for giving early morning mass to guests at the monastery. The interior of the building is divided into a large, open fireplace and the entrance hall. Attached to the pharmacy is a 19th-century carriage house , now a museum, that stands on top of a chapel built around 1480. The foundations of the chapel's choir are still extant behind the carriage house, as are
10961-533: The room's star vaults , which are clad in red frescoes from 1517. One of the captstones for the pillars depicts, unusually, eight eagles. The keystones of the vaults depict the Four Evangelists , the Lamb of God , and an angel blowing a trumpet. At the southeast corner of the chapter house is a small chapel in a bay window . A staircase on the east side of the cloister leads to the monks' dormitory. A corridor on
11074-620: The ruins of the Pfründhaus, where donors who had bought a life pension from the monastery resided. The building was erected in 1430 and used as a poorhouse in the 19th century until it was destroyed by fire in January 1892. In the southeast corner of the complex is the Faustturm, the tower where Johann Georg Faust is alleged to have lived while staying at the monastery in 1516. As was customary with Cistercian monasteries, Maulbronn stands on top of
11187-436: The second floor is a museum room detailing post-monastic life at Maulbronn. The nearby Frühmesserhaus displays a three-panel display made by the monks of Maulbronn documenting its foundation and attached circumstances. Within the monastery complex is a three-part literary museum, "Besuchen-Bilden-Schreiben", operated by the state of Baden-Württemberg . The first of these, "Visit" exhibits Maulbronn's image in literature. Next
11300-430: The second half of the 13th century it was granted legal jurisdiction over its territories by Pope Alexander IV . Per the rules of the Cistercian Order, its lands had to be worked by its lay brothers . However, the number of lay brothers at Maulbronn dwindled over the 13th century, owing to conflict between them and the monks, and as a result the monastery increasingly relied on hired laborers to work its land. Around 1236,
11413-529: 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
11526-419: 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,
11639-524: 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
11752-454: 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
11865-477: The western wall of the monastery are what used to be the blacksmithy and wheelwright 's workshops. East of the blacksmith is the former mews , which has been Maulbronn's city hall since the early 19th century. The building was converted in 1600 from its original Gothic appearance into the present Renaissance style structure. Just north of the city hall is the Haberkasten, used as a granary , and adjacent to that
11978-430: 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
12091-411: Was decorated with wrought iron and parchment that would have been glued onto the door and painted red. Immediately north of the abbey church is the cloister, the southern portion of which was built by the Master of the Paradise's workshop from 1210 to 1220. Lay brothers could enter or leave the cloister from a corridor on its west side. This leads to a flight of stairs to the lay brothers' dormitory, and
12204-566: Was pawned to Maulbronn Monastery , and by that time several gems and pearls had been taken out. In 1988, the crown featured in the Age of Chivalry exhibition at the Royal Academy of Arts in London – the first time it had returned to England since 1401. Diamond Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic . Diamond as
12317-420: Was protected by a stone wall, a drawbridge gate, and five towers. The origins of these structures is in the 13th century. The complex is still entered through the gatehouse, at its southwest corner, though the drawbridge is no longer present. The half-timber building on the back of the gatehouse was built around 1600 and the roof in 1751. Just behind the gatehouse are the pharmacy , originally an inn , and
12430-406: Was restored by a London goldsmith, who added a twelfth rosette and replaced the missing emerald and pearls on the fleurons. The new rosette contained 12 pearls, 3 diamonds, 3 balas rubies, and 1 sapphire. In total, 1 + 6 ⁄ 8 ounces (50 g) of gold were added to the crown. Blanche wore the crown at her wedding, which took place on 6 July 1402 at Cologne Cathedral in Germany. In 1421, it
12543-450: Was rich in water and, though it was also near the Roman road running from Speyer to Cannstatt , was isolated. Construction of the Maulbronn Monastery complex began soon thereafter and was largely completed by 1200–01; the abbey church was consecrated in 1178 by Arnold I , Archbishop of Trier . The new abbey at Maulbronn soon began a period of steady economic growth and legal security with
12656-583: Was the Wittelsbach King Rupert of Germany , who also took the German throne after the deposition of King Wenceslaus . A marriage between Rupert's eldest surviving son, Louis , and Henry IV's eldest daughter, Blanche, was soon arranged. On 7 March 1401, the marriage contract was signed in London , and the bride's dowry was fixed at 40,000 nobles . In 1402, prior to the wedding of Blanche and Louis III, it
12769-471: Was valued at £246 13s 4d . It was recorded again in a 1399 list of royal jewels being moved across London which had been owned by the deposed Richard II and others. Therefore, the crown had most likely belonged to Queen Anne of Bohemia , the wife of Richard II, whom she married in 1382. It may have been produced in Bohemia , but elements such as beading on the stems suggest Paris, though the maker might have been
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