Comparison analysis by the optical spectrum and the report of the place of origin for natural(unenhanced) and heated tanzanite

Abstract

We had the analysis to use the tanzanite which are mined at 500 meters underground by the cooperation of ELISARIA MSUYA MAININNG company which owned B block in 4 block in Tanzania.At the first time , we polished the rough stone of Tanzanite which we got at 500 meters underground and then we observed their inclusion by microscope. After that we heated these polished samples each 100°C, 200°C, 300°C, 350°C, 400°C, 450°C　ａｎｄ　500°C　for 3 hours and got the result for the changing and the data of optical spectrum in comparison with before and after heated. Our purposes of this test is what we must got the sample stones in rough state by the mine directly, because we usually get Tanzanite which had already done heated treatment by low temperature. I chose B block on this time and also examine the ratio of appearance of tanzanite in B block to divide the quality each Gem quality, Jewelry quality and accessories quality into three phases . The market prices are decided the evaluation of the quality and the demand. We report the result of the analysis and the place of origin situation.