algt colored stone identification report identification species ................................................................................ natural zoisite variety ............................................................................................ tanzanite description shape & cutting style ............................................... oval, mixed cut total carat weight .................................................................. 4.87 carat color .................................................................................... see comments transparency ......................................................................... transparent additional grading characteristics origin ................................................................................................ tanzania origin determination is an expert opinion based on microscopic examination, spectroscopic features and chemical trace element analysis. comments total 7 stones. average carat weight: 0.69 ct. color: light to intense purplish blue / bluish purple. 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.