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Emerald |
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emerald, the green variety of beryl beryl , mineral, a silicate of beryllium and aluminum, Be3Al2Si6O18, extremely hard, occurring in hexagonal crystals that may be of enormous size and are usually white, yellow, green, blue, or colorless. ..... Click the link for more information. , of which aquamarine is the blue variety. Chemically, it is a beryllium-aluminum silicate whose color is due to small quantities of chromium compounds. The emerald was highly esteemed in antiquity; the stones were used for ornaments in early Egypt where some of the first emeralds were mined. The finest emeralds are found in South America in Colombia, where they have been mined for over 400 years. The gem was a favorite in pre-Columbian Mexico and Peru, where it was cut in intricate designs. The treasure taken back to Spain by early explorers included emeralds. Good emeralds are the most highly valued of gem stones. India, Zimbabwe, and Australia are minor sources of the natural stones. Synthetic emeralds are also manufactured in Germany, France, and the United States. The Oriental emerald, a different gem, is the transparent green variety of corundum corundum , mineral, aluminum oxide, Al2O3. The clear varieties are used as gems and the opaque as abrasive materials. Corundum occurs in crystals of the hexagonal system and in masses. ..... Click the link for more information. . emeraldGrass-green variety of beryl that is highly valued as a gemstone. Its physical properties are those of beryl. Its refractive and dispersive powers (i.e., its capacity to deflect light and to break white light into its component colours) are not high, so cut stones display little brilliancy or fire (flashes of colour). The colour that gives this gem its value is due to the presence of small amounts of chromium. The most important production of fine quality gem material is from Colombia; emeralds are also mined in Russia, Australia, South Africa, and Zimbabwe. Synthetic emeralds are identical to natural crystals and may rival them in colour and beauty. emerald 1. a green transparent variety of beryl: highly valued as a gem 2. a. the clear green colour of an emerald b. (as adjective): an emerald carpet emerald [′em·rəld] (mineralogy) Al2(Be3Si6O18) A brilliant-green to grass-green gem variety of beryl that crystallizes in the hexagonal system; green color is caused by varying amounts of chromium. Also known as smaragd. emerald May. [Am. Gem Symbolism: Kunz, 319–320] See : Birthstones emerald relieves diseases of the eye. [Gem Symbolism: Kunz, 370] See : Healing
Emerald a mineral that is a transparent variety of beryl tinged with an admixture of Crj03 to a deep grass-green color. Emeralds are found in crystals and their concretions, usually intergrown in micaceous rock, quartz, or feldspar. The crystals, measuring 2–5 cm by 0.5–2 cm, rarely larger, are fractured. The larger deposits are connected with zones of the contact alteration of amphibolites, magnesial schist, and serpentinites by granitic pegmatites. Emeralds are also found in quartz feldspar veins and in altered schistose-carbonate rocks. Deposits are rare and are mainly in the USSR (Urals), Republic of South Africa (Transvaal), and Colombia (Muzo). Emeralds are highly valued as gems; those that are large (more than 5 carats), flawless, and have a deep, rich color are considered to be more valuable than diamonds. Synthetic emeralds (so-called igmeralds) are made, but their crystals are often fissured and no larger than 0.5 by 3 cm. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
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