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Amethyst __LINK__


Amethyst is a violet variety of quartz. The name comes from the Koine Greek αμέθυστος amethystos from α- a-, "not" and μεθύσκω (Ancient Greek) methysko / μεθώ metho (Modern Greek), "intoxicate", a reference to the belief that the stone protected its owner from drunkenness.[1] Ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication.




amethyst



Green quartz is sometimes incorrectly called green amethyst; this is a misnomer and not an appropriate name for the material, as the proper terminology is prasiolite.[8] Other names for green quartz are vermarine or lime citrine.


The color of amethyst has been demonstrated to result from substitution by irradiation of trivalent iron (Fe3+) for silicon in the structure,[4][12] in the presence of trace elements of large ionic radius,[3] and to a certain extent, the amethyst color can naturally result from displacement of transition elements even if the iron concentration is low. Natural amethyst is dichroic in reddish violet and bluish violet,[4] but when heated, turns yellow-orange, yellow-brown, or dark brownish and may resemble citrine,[13] but loses its dichroism, unlike genuine citrine. When partially heated, amethyst can result in ametrine.


Amethyst is produced in abundance in the state of Rio Grande do Sul in Brazil where it occurs in large geodes within volcanic rocks.[15][16][17][18] Many of the hollow agates of southwestern Brazil and Uruguay contain a crop of amethyst crystals in the interior. Artigas, Uruguay and neighboring Brazilian state Rio Grande do Sul are large world producers, with lesser quantities mined in Minas Gerais and Bahia states.[14]


Amethyst is also found and mined in South Korea.[19] The large opencast amethyst vein at Maissau, Lower Austria, was historically important,[1] but is no longer included among significant producers.[14] Much fine amethyst comes from Russia, especially near Mursinka in the Ekaterinburg district, where it occurs in drusy cavities in granitic rocks.[1][14] Amethyst was historically mined in many localities in south India,[1] though these are no longer significant producers.[14] One of the largest global amethyst producers is Zambia in southern Africa, with an annual production around 1000 tons.[20]


The Greeks believed amethyst gems could prevent intoxication,[23] while medieval European soldiers wore amethyst amulets as protection in battle in the belief that amethysts heal people and keep them cool-headed.[24] Beads of amethyst were found in Anglo-Saxon graves in England.[25] Anglican bishops wear an episcopal ring often set with an amethyst, an allusion to the description of the Apostles as "not drunk" at Pentecost in Acts 2:15.[26]


The meaning of amethyst varies from time to time and culture, which is why amethyst has different meanings in Feng Shui and focuses on increasing wealth. In ancient China, it was also used as a powerful tool to remove negative energies and drive away the hazards of daily life.[self-published source?]


Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are the same as those of natural amethyst, and it cannot be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). One test based on "Brazil law twinning" (a form of quartz twinning where right- and left-hand quartz structures are combined in a single crystal[27]) can be used to identify most synthetic amethyst rather easily. Synthesizing twinned amethyst is possible, but this type is not available in large quantities in the market.[6]


Treated amethyst is produced by gamma ray, X-ray, or electron-beam irradiation of clear quartz (rock crystal), which has been first doped with ferric impurities. Exposure to heat partially cancels the irradiation effects and amethyst generally becomes yellow or even green. Much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst".[1][28]


Tibetans consider amethyst sacred to the Buddha and make prayer beads from it.[35] Amethyst is considered the birthstone of February.[36] In the Middle Ages, it was considered a symbol of royalty and used to decorate English regalia.[36] In the Old World, amethyst was considered one of the cardinal gems, in that it was one of the five gemstones considered precious above all others, until large deposits were found in Brazil.[37]


Until the 18th century, amethyst was included in the cardinal, or most valuable, gemstones (along with diamond, sapphire, ruby, and emerald), but since the discovery of extensive deposits in locations such as Brazil, it has lost most of its value.[37] It is now considered a semiprecious stone.[38]


Collectors look for depth of color, possibly with red flashes if cut conventionally.[39] As amethyst is readily available in large structures, the value of the gem is not primarily defined by carat weight. This is different from most gemstones, since the carat weight typically exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed.[40]


The highest-grade amethyst (called "Deep Russian") is exceptionally rare. When one is found, its value is dependent on the demand of collectors. The highest-grade sapphires or rubies are still orders of magnitude more expensive than amethyst.[6]


Amethyst has a Mohs hardness of 7 and does not break by cleavage. That makes it durable enough for use in rings, bracelets, earrings, pendants, and any type of jewelry. Enormous deposits of amethyst in South America and Africa provide enough amethyst to keep the price low. Most people can easily afford amethyst.


While the word "amethyst" makes most people think of a dark purple gem, amethyst actually occurs in many purple colors. The purple color can be so light that it is barely perceptible or so dark that it is nearly opaque. It can be reddish purple, purple, or violetish purple. Amethyst exists in this wide range of colors.


Today much of the light amethyst is used to cut small calibrated stones for use in mass-market jewelry. Most of the premium reddish purple color amethyst is being used in high-end or designer jewelry.


Creative people have come up with a variety of adjectives to describe shades of amethyst. These include: orchid and lavender for lighter colors; grape, indigo or royal for darker colors; and raspberry or plum for reddish colors. While these names can be useful in conveying a generalized color, they are by no means precise or clearly understood by everyone.


The first step in amethyst receiving its purple color begins during crystal growth. That is when trace amounts of iron are incorporated into a growing quartz crystal. After crystallization, gamma rays, emitted by radioactive materials within the host rock, irradiate the iron to produce the purple color.


Amethyst crystals grow slowly and the composition of the fluids delivering the iron and the silica needed for crystal growth can vary. The darkest color of amethyst forms when the largest amount of iron is incorporated into the growing crystal. That is what causes color zoning.


Color zoning influences the marketability and value of amethyst. Most people want a gem with a rich and uniform color. As a result, gems of uniform color - no color zoning - are the most desirable and the most valuable.


Small amounts of amethyst are found at many locations throughout the world in igneous, metamorphic, and sedimentary rocks. Faceting, cabbing and ornamental grade amethyst can be found in all of these locations; however, the amount is usually insufficient to support an ongoing mining operation.


Amethyst has been produced at many locations in the United States. Much of it has been as a byproduct of other mining operations. Today, the only commercially run amethyst mine in the United States is the Four Peaks Mine in Arizona. The mine is well known for producing amethyst with a reddish purple color. The deposit was also known by Native Americans because a few amethyst arrowheads have been found nearby. Some of the amethyst in the Spanish crown jewels may be from this deposit, brought back to Spain by Spanish explorers. [1]


The amethyst geode market is very strong, with many tons of them being sold at the Tucson Gem and Mineral Show alone. Small amethyst geodes are one of the most ubiquitous geological items offered for sale. They can be found at gem shows, rock shops, metaphysical stores, and novelty shops around the world.


Although specimens of this material are still called "grape agate", a more appropriate name is "botryoidal amethyst". In the gem and mineral trade, incorrect names such as "grape agate" are called "misnomers".


Some prasiolite is also produced by irradiation of natural amethyst. This produces prasiolite with a lighter green color. This color can be lost if the material is heated to temperatures over 150 degrees Celsius.


However, with a hardness of 7, it can come in contact with a variety of common objects that can produce a scratch on its surface. Accidental scrapes on hard objects or abrasion with other gems of equal or greater hardness in a jewelry box can cause damage. Amethyst is also a brittle material that can be chipped or scratched by impact. It is best not to wear amethyst jewelry during an activity or at a location where this might occur.


Long-term storage of amethyst and amethyst jewelry is best done in a jewelry box or other dark location. The color of some amethyst can be subject to fading by prolonged exposure to direct sunlight or bright display lights.


Even though amethyst is not an extremely costly material, synthetic amethyst has been manufactured at least as far back as 1970. Since then an enormous number of items have been produced from synthetic amethyst by faceting, cabbing and carving. These have entered all levels of the jewelry trade. This has disappointed many jewelry consumers and made them hesitant to purchase amethyst. 041b061a72


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