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Untreated tanzanite is a trichroic gemstone, meaning that light that enters this anisotropic crystal gets refracted on different paths, with different colour absorption on each of the three optical axes. As a result of this phenomenon, a multitude of colors have been observed in various specimens: shades of purple, violet, indigo, blue, cyan ...
Zoisite occurs as prismatic, orthorhombic (2/m 2/m 2/m) crystals or in massive form, being found in metamorphic and pegmatitic rock. Zoisite may be blue to violet, green, brown, pink, yellow, gray, or colorless. Blue crystals are known under the name tanzanite. It has a vitreous luster and a conchoidal to uneven fracture. When euhedral, zoisite ...
Gemstones of the World revised 5th edition, 2013 by Walter Schumann ISBN 978-1454909538 Smithsonian Handbook: Gemstones by Cally Hall, 2nd ed. 2002 ISBN 978-0789489852 hide
In March 2007, IGI collaborated with the Tanzanite Foundation to help distribute jewelry certificates using a grading scale called the Tanzanite Quality Scale (TQS), for the gem called Tanzanite, which was discovered in Tanzania in the 1960s. [3] [4]
They have the ability to purchase large amounts of rough and have wholesale and retail distribution networks in place to facilitate the sale of loose tanzanite and finished jewellery. In August 2013 TanzaniteOne [4] announced they had opened an online boutique, www.tananiteoneonline, which sold tanzanite gemstones and tanzanite set gold ...
Peridot (gem-quality olivine) Perlite (volcanic glass) Phengite (variety of muscovite) Phosphorite (name given to impure, massive apatite.) Pimelite; Pitchblende (a massive impure form of uraninite) Plessite (mixture of kamacite and taenite) Potassium alum or potash alum (as a mineral, is called alum-(K))
Gemstone irradiation is a process in which a gemstone is exposed to artificial radiation in order to enhance its optical properties. High levels of ionizing radiation can change the atomic structure of the gemstone's crystal lattice , which in turn alters the optical properties within it. [ 1 ]
Phyllosilicates (from Greek φύλλον phýllon 'leaf'), or sheet silicates, form parallel sheets of silicate tetrahedra with Si 2 O 5 or a 2:5 ratio. The Nickel–Strunz classification is 09.E. All phyllosilicate minerals are hydrated, with either water or hydroxyl groups attached. Kaolinite. Examples include: Serpentine subgroup