Tanzanite Guide

​​Tanzanite is a blue to violet gemstone which is a member of the zoisite mineral group. It was discovered in 1967 in the hills of Northern Tanzania, which remains the sole source of tanzanite to this day. It was discovered by Manuel d’Souza in the Mererani Hills of Manyara Region in Northern Tanzania. Tanzanite was given its name by Tiffany & Co. who promoted the gemstone, resulting in its sudden popularity.

Tanzanite is pleotropic, which means that it reflects different colours depending on the viewing angle. In order to get the preferred blue or violet-blue hue, gem cutters must properly orient tanzanite gemstones. The vivid blue of tanzanite can rival fine sapphire and makes tanzanite an extremely desirable gemstone. This attractive colour is so sought after that tanzanite is routinely heated to enhance fine blue and violet hues and minimize the less desirable brownish tones.

The hardness measures 6.0 on the mohs scale. The refractive index (RI) is 1.696-1.703. Specific Gravity (SG) is 3.38. DIA grades accordingly to the ICSL grading system. 

Common Shapes​

Colour (Hue) / Saturation

Colour grading is based on the intensity of the colour, regardless of whether the stone is blue or violet. 

We use the “A” System grades which ranges from “A” for pale to “AAA+” for Vivid..

Saturation is the strength of the colour.


​Clarity refers to any natural defect or inclusion present in the tanzanite gemstone.

Tanzanite clarity ranges from the exceptional Loupe Clean (LC) to less desirable Heavily Included (HI).

Tanzanite Analysis

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