Tanzanite Quality and Treatment

Tanzanite’s bluish purple color is close to the color of a blue sapphire but its intense violet blue hue is a color all its own.

Cutting Tanzanite

Cutting plays an important part in the display of its color and financial considerations are given to the cutting of the tanzanite rough.  When cutting tanzanite to show off its bluish purple color, rough is not wasted.  That is why bluish purple tanzanite is so plentiful.  When cutting, the cutter must decide between a smaller stone of the higher quality of the intense violet blue hue or a larger tanzanite in the bluish purple hue. Tanzanite rates 6 to 7 out of 10 on the Mohs hardness scale making the everyday wear of a tanzanite ring risky. Wearing tanzanite as a pair of earrings or as a necklace would be a better option as it is unlikely that it will be bumped. Tanzanite is sensitive to accidental bumps or thermal shock. Most tanzanite jewelry is faceted and is cut in the shapes of oval, cushion, octagon or trillion cut.  To see larger tanzanite, you will see them in museums and private collections.

Treatment of Tanzanite

Surprisingly, untreated tanzanite is a brownish color.  When it is heat treated, the beautiful bluish purple or intense violet blue is shown.  When the Mosai tribesman originally found tanzanite, it was a blue tanzanite which probably had its own heat source.  Ninety five percent of all tanzanite are heat treated.