Bright metallic platy micro crystals of graphite very rich across the top of matrix. Good locality example for the species. Small crystals of gemmy zoisite are present as well.The Merelani Hills in northern Tanzania became globally famous following the discovery of gem-quality blue zoisite in 1967, with commercial mining and international marketing launching in 1968 through a partnership with Tiffany and Company, and unlike temporary deposits, these active mines have no set closing date and continue operating today. Geologically, the region sits within the Mozambique Belt, where intense Neoproterozoic metamorphic activity folded and altered a narrow zone of graphite-rich gneisses, schists, and marbles. Within these unique host rocks, hydrothermal fluids and trace amounts of vanadium combined under high pressure and temperature to form the rare violet-blue variety of zoisite known commercially as tanzanite, which remains entirely unique to this single two-square-kilometer deposit.
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