2.31ct Cushion Cut Ultra Fine Violet Tanzanite Polished Gem Stone For Auction Is A 2.31ct Extra Fine Violet Tanzanite Cushion Cut / Faceted Stone. This Piece Has Excellent Polish & Grade In Color. Was given its name by Tiffany's who had exclusive marketing rights to it for the first few years after its discovery. Its name is a reflection of the only known source in Tanzania. Our gemstones are hand-selected with a strict criteria for cut, clarity, and color. All of our gemstones are inspected, evaluated, and screened by a GIA Certified Gemologist to guarantee quality and accuracy in grading. Natural Tanzanite Species: Zoisite Shape/Cut: Square Princess Clarity: VVS-VS Color: Fine Violet Polish: Excellent Specific Gravity: 3.35 Hardness (Mohs): 6-7 Treatment: Fine Polish / & Crisp Cut Origin: Tanzania View Photos For Further Details.