Emerald is a precious gemstone and various beryl minerals (Si 3 ) 6 ) is green by tracking the amount of chromium and sometimes vanadium. Beryl has a hardness of 7.5-8 on the Mohs scale. Most emeralds are very much included, so their toughness (resistance to damage) is classified as poor in general. Emerald is a cyclosilicate.
Video Emerald
Etimologi
The word "emerald" originates (through the Old French: esmeraude and middle English: emeraude emeraude ????????? (smaragdos; "green gems").
Maps Emerald
Properties that specify a value
Emeralds, like all colored gems, are judged using four basic parameters - four C s connoisseurship: colors , clarity, cut i> and heavy rust . Usually, in the colored gradations of colored gems, color is by far the most important criterion. However, in the emerald judgment, clarity is considered second. A good emerald should have not only the pure green green hue as described below, but also a high degree of transparency to be considered the best gem.
In the 1960s, the American jewelry industry changed the definition of emerald to include green beryl vanadium-bearing. As a result, emerald vanadium emeralds purchased as emeralds in the United States are unknown in Britain and Europe. In America, the distinction between traditional emeralds and new vanadium types is often reflected in the use of terms like "Colombian emeralds".
Color
In gemology, color is divided into three components: hue , saturation , and tone . Emeralds occur in colors ranging from yellow-green to blue-green, with the main hue always being green. Yellow and blue are the normal secondary colors found in emeralds. Only gems with medium to dark tones are considered emeralds; brightly colored gems known as the species of green beryl . The best emerald is about 75% tone on a scale where the tone is 0% colorless and 100% black opaque. In addition, the fine emerald will be saturated and has a bright color (vivid). Gray is a modifier or normal saturation mask found in emeralds; grayish green is a dull green color.
Clarity
Emeralds tend to have many inclusions and surface breaking loopholes. Unlike diamonds, where the magnifying standard, ie, 10ÃÆ' magnification, is used to assess clarity, the emerald is judged by the eye. Thus, if the emeralds have no visible inclusions in the eye (assuming normal visual acuity) then it is considered flawless. Stones that do not have surface breaking breaks are very rare and therefore almost all emeralds are treated ("oiled", see below) to improve visible clarity. Emeralds and gaps in the emerald are sometimes described as jardin (French for garden ), due to their mossy appearance. Imperfections are unique to each emerald and can be used to identify specific stones. Clear-eye rock of clear main green color (as described above), with no more than 15% of any secondary or combination color (either blue or yellow) with medium-dark tones, the highest price order. Relative uniformity motivates emerging cuts in cabochon form, not in terms of shape. The emerald variety is most often given an oval piece, or a piece of emerald signature, a rectangular piece with an aspect around the top edge.
Treatment
Most emeralds are oiled as part of a post-cycle process, to fill cracks that reach the surface so that clarity and stability are improved. Cedar Oil, having the same refractive index, is often used in this widely adopted practice. Other liquids, including synthetic oils and polymers with a refractive index close to emeralds, such as Opticon , are also used. This treatment is usually applied in a vacuum chamber under mild heat, to open stone pores and allow the filling agent to absorb more effectively. The US Federal Trade Commission requires disclosure of this treatment when emeralds treated with oil are sold. The use of oil is traditional and largely accepted by trafficking of gems, though emeralds treated with oil are of considerably lower value than emeralds that are not treated equal to the same quality. Other treatments, such as the use of green oils, are not acceptable in trade. Gems are rated on a four-step scale; nothing , small , moderate and greatly improved. These categories reflect the level of improvement, not clarity . A gem rated not on an increasing scale may still show visible inclusions. The laboratory applies these criteria differently. Some gemologists consider only the presence of oil or polymer in addition. Others may ignore the oil traces if material presence does not improve the appearance of gemstones.
Emerald mines
Emeralds in ancient times were mined in Egypt at locations on Mount Smaragdus since 1500 BC, and India, and Austria since at least the 14th century. The Egyptian mines were exploited on an industrial scale by the Roman and Byzantine Empires, and later by Islamic conquerors. Mining stopped with the discovery of Colombian deposits, only the remains of the ruins.
Colombia is by far the world's largest emerald producer, which is 50-95% of world production, with amounts depending on year, source, and grade. Emerald production in Colombia has increased drastically in the last decade, increasing by 78% from 2000 to 2010. The three major emerald mining areas in Colombia are Muzo, Coscuez, and Chivor. The rare "trapiche" emeralds are found in Colombia, distinguished by dark fingers resembling rays.
Zambia is the second largest producer in the world, with a deposit area of ​​the Kafubu River (Kagem Mine) about 45 km (28 miles) southwest of Kitwe responsible for 20% of world-class gemstone production in 2004. In the first half of 2011, Mine Kagem produces 3.74 tons of emeralds.
Emeralds are found worldwide in countries like Afghanistan, Australia, Austria, Brazil, Bulgaria, Cambodia, Canada, China, Egypt, Ethiopia, France, Germany, India, Italy, Kazakhstan, Madagascar, Mozambique, Namibia, Nigeria, Norway, Pakistan, Russia, Somalia, South Africa, Spain, Switzerland, Tanzania, the United States, Zambia and Zimbabwe. In the US, emeralds have been found in Connecticut, Montana, Nevada, North Carolina, and South Carolina. In Canada, in 1997, emeralds were found in the Yukon.
Determination of origin
Since the onset of concerns about the origins of diamonds, research has been done to determine whether the mining location can be determined for emeralds already in circulation. Traditional research uses qualitative guidance such as emerald color, cutting style and quality, fractional filling type, and anthropological origin of mineral-containing artifacts to determine the location of emerald mines. More recent research using the diffuse X-ray diffraction spectroscopy method has found traces of chemical element differences between emeralds; even emeralds that are mined in close proximity to each other. American gemologist David Cronin and his colleagues have extensively examined the chemical signs of emeralds resulting from fluid dynamics and fine precipitation mechanisms, and their research shows the emerging chemical homogeneity of the same mining site and the statistical differences that exist between the emeralds from the site different mining. , including among three locations: Muzo, Coscuez, and Chivor, in Colombia, South America.
Synthetic emerald
Both hydrothermal and synthetic growth-flux have been produced, and methods have been developed to produce emerald overgrowth in colored beryl. The first commercially successful emerald synthesis synthesis process is Carroll Chatham, possibly involving the lithium vanadate flux process, because Chatham emeralds have no water and contain traces of vanadate, molybdenum and vanadium. Another large producer of emerald flux stone is Pierre Gilson Sr., whose product has been marketed since 1964. Emerald Gilson is usually grown on natural colored beryl seeds, which are coated on both sides. Growth occurs at a rate of 1 mm per month, typical seven-month growth produces a 7mm-thick emerald crystal.
The hydrothermal synthetic emerald has been associated with IG Farben, Nacken, Tairus, and others, but the first satisfactory commercial product was the Johann Lechleitner product from Innsbruck, Austria, which appeared on the market in the 1960s. These stones were originally sold under the names "Emerita" and "Symeralds", and they grew as thin layers of emerald on natural colored beryl. Later, from 1965 to 1970, the Linde Union Carbide Division produced fully synthetic emeralds with hydrothermal synthesis. According to their patents (caused by E.M. Flanigen), acidic conditions are essential for preventing chromium (which is used as a dye) from precipitates. Also, it is important that silicone-containing nutrients are kept away from other ingredients to prevent nucleation and limit growth in crystal seeds. Growth occurs through a process of diffusion reaction, aided by convection. The largest producer of current hydrothermal emeralds is Tairus, who has succeeded in synthesizing emeralds with a chemical composition similar to emeralds in the alkaline deposit in Colombia, and whose product came to be known as "created Colombian emerald" or "Tairus created the emerald". Luminescence in ultraviolet light is considered an additional test when making natural versus synthetic determinations, as many, but not all, natural emeralds are inert against ultraviolet light. Many synthetic also inert UV.
Synthetic emeralds are often referred to as "created", because their chemical composition and gemology are the same as their natural counterparts. The US Federal Trade Commission (FTC) has very strict rules about what can and what can not be called "synthetic" stones. The FTC says: "Ã,§ 23,23 (c) It is unfair or deceptive to use the word" grown in a laboratory "," laboratory-made "," [manufacturer's name] -dollected, "or" synthetic "by whatever name rock nature to describe any industrial product unless the industrial product basically has the same optical, physical, and chemical properties as a stone named. "
In culture and knowledge
Emeralds are regarded as traditional birthstones for May as well as traditional gemstones for signs of Cancer astrology.
One of the quaintter anecdotes about emeralds is told by a 16th-century historian, BrantÃÆ''me, which refers to many impressive emeralds under Cortez having been brought back to Europe from Latin America. In one of the most famous emeralds in Cortez, he has an engraved text, Inter Natos Mulierum non sur-rexit mayor ("Among those born of women there have never appeared greater, "Matthew 11:11) called to John the Baptist. BrantÃÆ'Â'me considers the beautiful and simple product carvings of the immoral world and considers this to be the cause of Cortez's disappearance from the precious pearls (which he dedicates a masterpiece, the beautiful and unparalleled pearls), and even over the death of Charles IX of France, who died shortly thereafter.
The main deity of one of India's most famous temples, Meenakshi Amman Temple in Madurai, is the goddess Meenakshi, whose idol is traditionally thought to be made of emerald stone.
The famous emerald
Gallery
See also
- Mineral list
- Colombian mineral industry
- Cardinal gem
References
Further reading
- Ali, Saleem H. (2006). The Emerald City: Emerald Mining in Brazil (Mining of gems in other countries) http://www.uvm.edu/envnr/gemecology/brazil.html
- Cooper, J. C. (ed.) (1992). Brewer's Myth and Legend . New York: Cassell Publishers Ltd. ISBN: 0-304-34084-7.
- Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20th ed.). New York: John Wiley and Sons. ISBNÃ, 0-471-80580-7.
- Sinkankas, John (1994). Emerald & amp; Other Beryls . Prescott, Ariz.: Geoscience Press. ISBNÃ, 0-8019-7114-4.
- Tavernier, Jean-Baptiste (1925 [1676]). Travel in India (second edition), Volume II. Edited by William Crooke and translated by V. Ball. London: Oxford University Press.
- Weinstein, Michael (1958). World of Gems . New York: Sheriden House. OCLCÃ, Â ± 519758.
- Wise, Richard W. (2003). The Secret of Trades of Gems: Connoisseur's Guide to Precious Gems . Lenox, Mass.: Brunswick House Press. ISBNÃ, 9780972822398. OCLCÃ, 55662640. Chapter Emerald online.
External links
- ICA International Emerald Page Gems Colored Gems Page
Source of the article : Wikipedia
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