Εxceptional Tanzanite gemstone suitable for jewellery or an investment-grade piece. Full physical ALGT Certificate included. Species .............................................................. Natural Zoisite Variety .............................................................. Tanzanite Shape & Cutting Style ........................................ Oval, Mixed Cut Measurements ...................................................... 7.57 x 6.44 x 4.29 mm Carat Weight ....................................................... 1.69 Carat Color ....................................................................... Intense Purplish Blue Transparency .................................................... Transparent Origin ....................................................................... Tanzania Origin determination is an expert opinion based on microscopic examination, spectroscopic features and chemical trace element analysis. Tanzanite is commonly heated at low temperature to improve its color. There is currently no scientific method available to determine whether this gemstone has been enhanced or not.