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48-560: Rubis is the French word for ruby . Rubis may refer to: Ruby Ruby is a pinkish red to blood-red colored gemstone , a variety of the mineral corundum ( aluminium oxide ). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires . Ruby is one of the traditional cardinal gems , alongside amethyst , sapphire , emerald , and diamond . The word ruby comes from ruber , Latin for red. The color of

96-456: A Fabry–Pérot etalon (or a Gires-Tournois etalon ). Modern lasers often use rods with antireflection coatings , or with the ends cut and polished at Brewster's angle instead. This eliminates the reflections from the ends of the rod. External dielectric mirrors then are used to form the optical cavity. Curved mirrors are typically used to relax the alignment tolerances and to form a stable resonator, often compensating for thermal lensing of

144-402: A wavelength of 694.3  nm , which is a deep red color. Typical ruby laser pulse lengths are on the order of a millisecond . A ruby laser most often consists of a ruby rod that must be pumped with very high energy, usually from a flashtube , to achieve a population inversion . The rod is often placed between two mirrors, forming an optical cavity , which oscillate the light produced by

192-400: A continuous train of pulses, giving scientists the opportunity to study the spiked output of ruby. The continuous ruby laser was the first laser to be used in medicine. It was used by Leon Goldman, a pioneer in laser medicine , for treatments such as tattoo removal, scar treatments, and to induce healing. Due to its limits in output power, tunability, and complications in operating and cooling

240-459: A large premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually pinker than garnet , although some rhodolite garnets have a similar pinkish hue to most rubies. The world's most valuable ruby to be sold at auction

288-540: A little chromium at red heat . In 1903, Verneuil announced he could produce synthetic rubies on a commercial scale using this flame fusion process, later also known as the Verneuil process . By 1910, Verneuil's laboratory had expanded into a 30 furnace production facility, with annual gemstone production having reached 1,000 kilograms (2,000 lb) in 1907. Other processes in which synthetic rubies can be produced are through Czochralski's pulling process , flux process, and

336-401: A method of q-switching , to concentrate the output into a single pulse. In 1962, Willard Boyle , working at Bell Labs , produced the first continuous output from a ruby laser. Unlike the usual side-pumping method, the light from a mercury arc lamp was pumped into the end of a very small rod, to achieve the necessary population inversion. The laser did not emit a continuous wave , but rather

384-508: A pink ruby rod, measuring 1 cm by 1.5 cm, and, on May 16, 1960, fired the device, producing the first beam of laser light. Theodore Maiman's original ruby laser is still operational. It was demonstrated on May 15, 2010, at a symposium co-hosted in Vancouver, British Columbia by the Dr. Theodore Maiman Memorial Foundation and Simon Fraser University , where Dr. Maiman was adjunct professor at

432-406: A possible alternative. Maiman, having worked with ruby for many years, and having written a paper on ruby fluorescence, felt that Schawlow was being "too pessimistic." His measurements indicated that the lowest energy level of pink ruby could at least be partially depleted by pumping with a very intense light source, and, since ruby was readily available, he decided to try it anyway. Also attending

480-581: A ruby is due to the element chromium . Some gemstones that are popularly or historically called rubies, such as the Black Prince's Ruby in the British Imperial State Crown , are actually spinels . These were once known as "Balas rubies". The quality of a ruby is determined by its color, cut, and clarity, which, along with carat weight, affect its value. The brightest and most valuable shade of red, called blood-red or pigeon blood, commands

528-553: Is lead glass filling. Filling the fractures inside the ruby with lead glass (or a similar material) dramatically improves the transparency of the stone, making previously unsuitable rubies fit for applications in jewelry. The process is done in four steps: If a color needs to be added, the glass powder can be "enhanced" with copper or other metal oxides as well as elements such as sodium, calcium, potassium etc. The second heating process can be repeated three to four times, even applying different mixtures. When jewelry containing rubies

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576-413: Is defined to be red. All other hues of the gem species corundum are called sapphire. Ruby may exhibit a range of secondary hues, including orange, purple, violet, and pink. Because rubies host many inclusions, their clarity is evaluated by the inclusions’ size, number, location, and visibility. Rubies with the highest clarity grades are known as “eye-clean,” because their inclusions are the least visible to

624-414: Is energized through optical pumping , typically by a xenon flashtube. Ruby has very broad and powerful absorption bands in the visual spectrum, at 400 and 550 nm, and a very long fluorescence lifetime of 3 milliseconds. This allows for very high energy pumping, since the pulse duration can be much longer than with other materials. While ruby has a very wide absorption profile, its conversion efficiency

672-710: Is heated (for repairs) it should not be coated with boracic acid or any other substance, as this can etch the surface; it does not have to be "protected" like a diamond. The treatment can be identified by noting bubbles in cavities and fractures using a 10× loupe. In 1837, Gaudin made the first synthetic rubies by fusing potash alum at a high temperature with a little chromium as a pigment. In 1847, Ebelmen made white sapphire by fusing alumina in boric acid. In 1877, Edmond Frémy and industrial glass-maker Charles Feil made crystal corundum from which small stones could be cut. In 1887, Fremy and Auguste Verneuil manufactured artificial ruby by fusing BaF 2 and Al 2 O 3 with

720-411: Is much lower than other mediums. In early examples, the rod's ends had to be polished with great precision, such that the ends of the rod were flat to within a quarter of a wavelength of the output light, and parallel to each other within a few seconds of arc. The finely polished ends of the rod were silvered ; one end completely, the other only partially. The rod, with its reflective ends, then acts as

768-571: Is the Sunrise Ruby , which sold for US$ 34.8 million. Rubies have a hardness of 9.0 on the Mohs scale of mineral hardness . Among the natural gems, only moissanite and diamond are harder, with diamond having a Mohs hardness of 10.0 and moissanite falling somewhere in between corundum (ruby) and diamond in hardness. Sapphire, ruby, and pure corundum are α-alumina, the most stable form of Al 2 O 3 , in which 3 electrons leave each aluminium ion to join

816-399: Is the most important factor. Color divides into three components: hue , saturation and tone . Hue refers to color as we normally use the term. Transparent gemstones occur in the pure spectral hues of red, orange, yellow, green, blue, violet. In nature, there are rarely pure hues, so when speaking of the hue of a gemstone, we speak of primary and secondary and sometimes tertiary hues. Ruby

864-485: Is the only country in mainland Europe to have naturally occurring rubies. They can mainly be found around the city of Prilep . Macedonian rubies have a unique raspberry color. A few rubies have been found in the U.S. states of Montana , North Carolina , South Carolina and Wyoming . Spinel , another red gemstone, is sometimes found along with rubies in the same gem gravel or marble. Red spinels may be mistaken for rubies by those lacking experience with gems. However,

912-760: The hydrothermal process . Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curved striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a perfect ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemological testing to determine their origin. Synthetic rubies have technological uses as well as gemological ones. Rods of synthetic ruby are used to make ruby lasers and masers . The first working laser

960-591: The 17th century techniques were developed to color foil red—by burning scarlet wool in the bottom part of the furnace—which was then placed under the imitation stone. Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from use by many gemological associations such as the Laboratory Manual Harmonisation Committee (LMHC). Ruby laser Ruby lasers produce pulses of coherent visible light at

1008-433: The 532 nm green light of frequency-doubled Nd:YAG , which often requires multiple pulses for large holograms. Many non-destructive testing labs use ruby lasers to create holograms of large objects such as aircraft tires to look for weaknesses in the lining. Ruby lasers were used extensively in tattoo and hair removal , but are being replaced by alexandrite and Nd:YAG lasers in this application. The ruby laser

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1056-525: The Aappaluttoq mine in Greenland began running. The rubies in Greenland are said to be among the oldest in the world at approximately 3 billion years old. The Aappaluttoq mine in Greenland is located 160 kilometers south of Nuuk, the capital of Greenland. The rubies are traceable from mine to market. The Montepuez ruby mine in northeastern Mozambique is situated on one of the most significant ruby deposits in

1104-511: The Al 2 O 3 crystal. However, the Cr ions are larger and have electron orbitals in different directions than aluminium. The octahedral arrangement of the O ions is distorted, and the energy levels of the different orbitals of those Cr ions are slightly altered because of the directions to the O ions. Those energy differences correspond to absorption in the ultraviolet, violet, and yellow-green regions of

1152-892: The International Colored Gemstone Association (ICGA) have adopted the broader definition for ruby which encompasses its lighter shades, including pink. Historically, rubies have been mined in Thailand, in the Pailin and Samlout District of Cambodia , as well as in Afghanistan , Australia , Brazil , Colombia , India , Namibia , Japan , and Scotland. After the Second World War , ruby deposits were found in Madagascar , Mozambique , Nepal, Pakistan, Tajikistan , Tanzania , and Vietnam . The Republic of North Macedonia

1200-452: The School of Engineering Science. Maiman's original laser was fired at a projector screen in a darkened room. In the center of a white flash (leakage from the xenon flashtube), a red spot was briefly visible. The ruby lasers did not deliver a single pulse, but rather delivered a series of pulses, consisting of a series of irregular spikes within the pulse duration. In 1961, R.W. Hellwarth invented

1248-496: The United States, a minimum color saturation must be met to be called a ruby; otherwise, the stone will be called a pink sapphire . Drawing a distinction between rubies and pink sapphires is relatively new, having arisen sometime in the 20th century. Often, the distinction between ruby and pink sapphire is not clear and can be debated. As a result of the difficulty and subjectiveness of such distinctions, trade organizations such as

1296-453: The absorption and emission of radiation. Depending on the concentration of the dopant, synthetic ruby usually comes in either pink or red. One of the first applications for the ruby laser was in rangefinding. By 1964, ruby lasers with rotating prism q-switches became the standard for military rangefinders , until the introduction of more efficient Nd:YAG rangefinders a decade later. Ruby lasers were used mainly in research. The ruby laser

1344-425: The conference was Gordon Gould . Gould suggested that, by pulsing the laser, peak outputs as high as a megawatt could be produced. As time went on, many scientists began to doubt the usefulness of any color ruby as a laser medium. Maiman, too, felt his own doubts, but, being a very "single-minded person," he kept working on his project in secret. He searched to find a light source that would be intense enough to pump

1392-598: The crystal during that time, they can stimulate more fluorescent photons to be emitted in-phase with them, thus strengthening the intensity of that red light. By arranging mirrors or other means to pass emitted light repeatedly through the crystal, a ruby laser in this way produces a very high intensity of coherent red light. All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Usually,

1440-458: The crystal growth process) to be ten to twenty times less than in the natural gemstones. Theodore Maiman says that "because of the low chromium level in these crystals they display a lighter red color than gemstone ruby and are referred to as pink ruby ." After absorbing short-wavelength light, there is a short interval of time when the crystal lattice of ruby is in an excited state before fluorescence occurs. If 694-nanometer photons pass through

1488-473: The finest red spinels, now heavily sought, can have values approaching all but the finest examples of ruby. The Mogok Valley in Upper Myanmar (Burma) was for centuries the world's main source for rubies. That region has produced some exceptional rubies; however, in recent years few good rubies have been found. In central Myanmar, the area of Mong Hsu began producing rubies during the 1990s and rapidly became

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1536-408: The late 1990s, a large supply of low-cost materials caused a sudden surge in supply of heat-treated rubies, leading to a downward pressure on ruby prices. Improvements used include color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them. The most common treatment is the application of heat. Most rubies at the lower end of

1584-472: The market are heat treated to improve color, remove purple tinge , blue patches, and silk. These heat treatments typically occur around temperatures of 1800 °C (3300 °F). Some rubies undergo a process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300 °C (2400 °F) for 20 to 30 minutes. The silk is partially broken, and the color is improved. Another treatment, which has become more frequent in recent years,

1632-445: The naked human eye. Rubies may also have thin, intersecting inclusions called silk. Silk can scatter light, brightening the gem's appearance, and the presence of silk can also show whether a ruby has been previously heat treated, since intense heat will degrade a ruby's silk. Improving the quality of gemstones by treating them is common practice. Some treatments are used in almost all cases and are therefore considered acceptable. During

1680-447: The race to build a working model began. Ruby had been used successfully in masers, so it was a first choice as a possible medium. While attending a conference in 1959, Maiman listened to a speech given by Schawlow, describing the use of ruby as a lasing medium. Schawlow stated that pink ruby, having a lowest energy-state that was too close to the ground-state, would require too much pumping energy for laser operation, suggesting red ruby as

1728-401: The red. Ruby lasers have declined in use with the discovery of better lasing media. They are still used in a number of applications where short pulses of red light are required. Holographers around the world produce holographic portraits with ruby lasers, in sizes up to a meter square. Because of its high pulsed power and good coherence length, the red 694 nm laser light is preferred to

1776-412: The regular octahedral group of six nearby O ions; in pure corundum this leaves all of the aluminium ions with a very stable configuration of no unpaired electrons or unfilled energy levels, and the crystal is perfectly colorless, and transparent except for flaws. When a chromium atom replaces an occasional aluminium atom, it too loses 3 electrons to become a chromium ion to maintain the charge balance of

1824-597: The rod, and an elliptical pumping cavity of high reflectivity, to direct the energy into the rod. He found his light source when a salesman from General Electric showed him a few xenon flashtubes , claiming that the largest could ignite steel wool if placed near the tube. Maiman realized that, with such intensity, he did not need such a highly reflective pumping cavity, and, with the helical lamp, would not need it to have an elliptical shape. Maiman constructed his ruby laser at Hughes Research Laboratories, in Malibu, California. He used

1872-411: The rod. Ruby also absorbs some of the light at its lasing wavelength. To overcome this absorption, the entire length of the rod needs to be pumped, leaving no shaded areas near the mountings. The active part of the ruby is the dopant , which consists of chromium ions suspended in a synthetic sapphire crystal. The dopant often comprises around only 0.05% of the crystal, but is responsible for all of

1920-415: The rough stone is heated before cutting. These days, almost all rubies are treated in some form, with heat treatment being the most common practice. Untreated rubies of high quality command a large premium. Some rubies show a three-point or six-point asterism or "star". These rubies are cut into cabochons to display the effect properly. Asterisms are best visible with a single-light source and move across

1968-400: The ruby's fluorescence , causing stimulated emission . Ruby is one of the few solid state lasers that produce light in the visible range of the spectrum, lasing at 694.3 nanometers, in a deep red color, with a very narrow linewidth of 0.53 nm. The ruby laser is a three level solid state laser . The active laser medium (laser gain/ amplification medium) is a synthetic ruby rod that

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2016-403: The spectrum. If one percent of the aluminium ions are replaced by chromium in ruby, the yellow-green absorption results in a red color for the gem. Additionally, absorption at any of the above wavelengths stimulates fluorescent emission of 694-nanometer-wavelength red light, which adds to its red color and perceived luster . The chromium concentration in artificial rubies can be adjusted (in

2064-491: The stone as the light moves or the stone is rotated. Such effects occur when light is reflected off the "silk" (the structurally oriented rutile needle inclusions) in a certain way. This is one example where inclusions increase the value of a gemstone. Furthermore, rubies can show color changes—though this occurs very rarely—as well as chatoyancy or the "cat's eye" effect. Generally, gemstone-quality corundum in all shades of red, including pink, are called rubies. However, in

2112-511: The world's main ruby mining area. The most recently found ruby deposit in Myanmar is in Namya (Namyazeik) located in the northern state of Kachin . In Pakistani Kashmir there are vast proven reserves of millions of rubies, worth up to half a billion dollars. However, as of 2017 there was only one mine (at Chitta Katha) due to lack of investment. In Afghanistan , rubies are mined at Jegdalek. In 2017

2160-429: The world, although, rubies were only discovered here for the first time in 2009. In less than a decade, Mozambique has become the world's most productive source for gem-quality ruby. Rubies, as with other gemstones, are graded using criteria known as the four Cs, namely color, cut, clarity and carat weight. Rubies are also evaluated on the basis of their geographic origin. In the evaluation of colored gemstones, color

2208-563: Was made by Theodore H. Maiman in 1960. Maiman used a solid-state light-pumped synthetic ruby to produce red laser light at a wavelength of 694 nanometers (nm). Ruby lasers are still in use. Rubies are also used in applications where high hardness is required such as at wear-exposed locations in mechanical clockworks, or as scanning probe tips in a coordinate measuring machine . Imitation rubies are also marketed. Red spinels , red garnets , and colored glass have been falsely claimed to be rubies. Imitations go back to Roman times and already in

2256-462: Was the first laser to be made functional. Built by Theodore Maiman in 1960, the device was created out of the concept of an "optical maser," a maser that could operate in the visual or infrared regions of the spectrum. In 1958, after the inventor of the maser, Charles Townes , and his colleague, Arthur Schawlow , published an article in the Physical Review regarding the idea of optical masers,

2304-458: Was the first laser used to optically pump tunable dye lasers and is particularly well suited to excite laser dyes emitting in the near infrared. Ruby lasers are rarely used in industry, mainly due to low efficiency and low repetition rates. One of the main industrial uses is drilling holes through diamond , because ruby's high-powered beam closely matches diamond's broad absorption band (the GR1 band) in

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