Turquoise / Nishapur / large pendant / cabochon / new- 11.44 g - (1)

ishapur Turquoise Pendant / Cabochon / new Set in 925 sterling silver Includes leather cord Weight: 11.44 g !!! (weighed without the leather cord) 23.9 mm x 19.3 mm x 11.1 mm New and unworn The turquoise mineral is a relatively rare hydrated copper–aluminum phosphate from the mineral class of “phosphates, arsenates and vanadates” with the chemical composition CuAl6(PO4)4(OH)8·4H2O. In place of aluminum, iron as Fe3+ can be incorporated into the crystal structure (diadochy), hence the chemical formula is also often given as Cu(Al,Fe)6(PO4)4(OH)8·4H2O. Turquoise crystallizes in the triclinic crystal system and is the eponym of a group of minerals with the same structure but different composition, the turquoise group, with the other members faustite, chalkosiderite, aheylite and planerite. In nature turquoise usually forms grape-like or earthy-mass mineral aggregates. Crystals visible to the naked eye are very rare and then only a few millimeters in size with a prismatic to needle-like habit. Its characteristic blue-green color is the reason turquoise derives its name. Turquoise is used exclusively as a gemstone for jewelry. Shipping as insured registered mail

Estimate:£1.69

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