turquoise(redirected from turquoises)
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turquoise,hydrous phosphate of aluminum and copper, Al2(OH)3PO4·H2O+Cu, used as a gem. It occurs rarely in crystal form, but is usually cryptocrystalline. Turquoise is opaque and has a waxy luster; the color varies from greenish gray to sky-blue. The sky-blue varieties are the most valued as gems, but because of their porosity they easily absorb dirt and grease and change in color to an unattractive green. Exposure to heat or sunlight is also injurious to the color of the turquoise. The finest specimens come from Iran; other sources are the Sinai peninsula and the SW United States, especially New Mexico, Nevada, Arizona, and Colorado. Turquoise matrix is a rock including fragments of turquoise, cut as a gem stone. Variscite, the hydrated phosphate of aluminum, is sometimes used as a substitute for turquoise. It occurs in crystals of the orthorhombic system and in massive form; minable deposits are found in Utah.
a mineral of the chemical composition CuAl6[P04]4(OH)8·4H2O. It crystallizes in a tricline system. It usually forms compact, cryptocrystalline masses, kidney-shaped aggregates, incrustations, thin veins, and so on. Its hardness on the mineralogical scale is 5–6; its density is 2,600–2,800 kg/m3. The luster is dull and waxy. It is distinguished by a beautiful sky-blue or greenish-blue color. The formation of turquoise is associated with the weathering of feldspar rocks rich in Al2O3 and phosphates (apatite, phosphorite, and others) under the influence of surface waters that contain copper ions. Turquoise is sometimes formed by the replacement of parts of the skeleton of fossil animals (so-called odontolite). Owing to its beautiful color (particularly in polished form), it is widely used in art and jewelry items as a semiprecious stone. The largest deposit of turquoise is at Nishapur in Iran. In the USSR, turquoise is found in Middle Asia and Kazakhstan.
G. P. BARSANOV
What does it mean when you dream about turquoise?
A precious stone of blue and green mined by Native Americans throughout the southwestern United States, the turquoise has spiritual significance. It is the sacred stone of the Navajo associated with natural forces and healing.