Turquoise pieces from the '79 mine in the U.S.A.

The mineral turquoise is a hydrated copper-aluminum-phosphate with the chemical formula CuAl6 (PO4) 4 (OH) 8 · 4 (H 2 O). The green, yellow, gray, light blue, but typical blue green turquoise has a wasglans a pale blue and white stripe color. The crystal system is triclinic and the cleavage is perfect according to the crystal surface [001] as well [010]; moreover it almost comes only forms cryptocrystalline for so fission in practice to observe. The average density is 2.7 and the hardness is from 5 to 6. Turquoise is not radioactive. The mineral turquoise is named after Turkey, the country through which it passed when the mineral first reached Europe; otherwise it is not known to be in Turkey. The color turquoise is named after this mineral. Turquoise is primarily found as a secondary mineral in copper ores. The type of location is the deposition Nishapur in Iran. Also in the Sinai and the mineral was mined in Serabit el-Khadim is a temple dedicated to the Egyptian "Lady Torquoise" (the goddess Hathor). Turquoise is used as a gemstone. During the Ottoman Empire was turquoise exported as precious minerals, especially to Persia. Currently turquoise is mined in Mexico, the United States, China and Iran. Imitation Turquoise was made for the first time in 1972 in France, but the properties of these imitation different from those of the natural varieties. Yet the best-selling turquoise now synthetic.