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Turquoise deposits probably form in more than one way. [16] However, a typical turquoise deposit begins with hydrothermal deposition of copper sulfides . This takes place when hydrothermal fluids leach copper from a host rock, which is typically an intrusion of calc-alkaline rock with a moderate to high silica content that is relatively oxidized .
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Turquoise (/ ˈ t ɜːr k (w) ɔɪ z / TUR-k(w)oyz) is a cyan color, based on the mineral of the same name.The word turquoise dates to the 17th century and is derived from the French turquois, meaning 'Turkish', because the mineral was first brought to Europe through Turkey from mines in the historical Khorasan province of Iran (Persia) and Afghanistan today.
Chrysoprase, chrysophrase or chrysoprasus is a gemstone variety of chalcedony (a cryptocrystalline form of silica) that contains small quantities of nickel. Its color is normally apple-green, but varies from turquoise-like cyan to deep green. The darker varieties of chrysoprase are also referred to as prase.
This type of patina is formed by corrosion, what elements the air might hold, residue from the wear of the carbon brush, and moisture; thus, the patina needs special conditions to work as intended. Patinas can also be found in woks or other metal baking dishes. The process of applying patinas to cookware is known as seasoning.
The site was rediscovered in 1809 by Ulrich Jasper Seetzen, and since then has seen several excavation teams, Richard Lepsius's excavation in 1845 being the first. Major C. K. McDonald's visits to the site, including residence at the site from 1854–1866 (and an effort to mine turquoise there) resulted in only surface finds (arrowheads and such) with no further excavation.
The Jewel Box contains jewelry primarily made of turquoise, and has information on the different types of turquoise and which mines they come from. The Frontier Gallery features several works by Chinese-American artists, depicting life as it was for Chinese-Americans during that time in history.
Most of the white varieties of turquoise are chalk-like with a Mohs hardness of 1, and are not as hard or durable as howlite, and subsequently require stabilization in order to be used in jewelry, which has resulted in howlite being more popular for use in jewelry than the artificially stabilized white forms of the mineral turquoise. [9]