Tuesday, June 23, 2015

Green Turquoise gemstone beads

For most of time, blue turquoise varieties were considered most desirable, while green turquoise was thought to be inferior. It was believed by the ancients that blue turquoise did not lose color over time, and that stones with lesser blues would eventually fade to green. However, history has shown that this is not the case. Since recent times, the demand for green turquoise gemstone beads has increased. In fact, there are several green turquoise varieties that are now considered to be some of the top ranked turquoise available today, including many of Nevada's turquoise and also China's 'Skyhorse' and 'China Mountain' varieties.
Turquoise is colored by traces of copper, the same element responsible for the green-blue color of Paraiba tourmaline. Its greens can range from shades of bluish-green to apple-green or lime-green. Generally, if turquoise forms with less copper and more aluminum, the material tends to be green. But when zinc is also present, it can result a rare lime-green color; a rare hue found only in a few areas, including Mongolia and the United States. Much of the green turquoise from the USA gets its color from iron, rather than aluminum; if iron or zinc replaces the aluminum entirely, the material becomes iron-rich chalcosiderite or zinc-rich faustite. Veining is normal for green turquoise and matrix colors can vary from brown to black, and even from golden to yellow. Black matrix is usually owed to iron pyrite, while brown is usually caused by iron oxide. Golden colors may be due to rhyolite matrix.

Green turquoise is indeed a rarity, but it can be found in a few areas around the world. Mongolia and Egypt's turquoise deposits are known to occur more green than blue. Mines from India are also known to produce green turquoise. China has some very desirable deposits, but much of China's turquoise is often enhanced. The United States is today's leading producer of green turquoise. 

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