This is a very nice natural TANZANITE from the mines of Tanzanie…Pear cabochon…4,01 cts…10,90 x 7,89 x 5,69mm…

We also have a store for synthetic stones as ruby, sapphires and CZ….You can visit my store at: https://www.gemstonesauctions.com/stores/jeanclaude

Tanzanite was enthusiastically celebrated as “Gemstone of the 20th Century” after its discovery in 1967. It is named after the East African state of Tanzania where its only deposit has been found. The legendary New York jewelers Tiffany & Co were the first to promote tanzanite as a fine gemstone. Tanzanite is a variety of the zoisite species. In good quality the color is ultramarine to sapphire blue. The most popular color is a saturated blue, which shows a purplish hue shimmering around it. Tanzanite needs experienced cutters to treat it carefully, as the stone has perfect cleavage in one direction. The stone is cut in all imaginable shapes and forms, from classical round cuts to imaginative designer cuts. Nearly all tanzanite has been heat treated to produce the striking violet-blue color.

Species: Zoisite Color: Sapphire blue, amethyst, violet Chemical composition: Ca2Al3(Sio4)3(OH) calcium aluminum silicate Crystal system: Orthorhombic, multifaceted prisms, mostly striated Hardness: 6.5-7 (Mohs scale) Specific gravity: 3.35 Refractive index: 1.691 - 1.700 Birefringence: +0.009 Color of streak: White, Absorption spectrum: 595, 528, 455 Fluorescence: None