|Frequently Asked Questions (FAQ) / Difference Sapphire - Tanzanite|
What is the difference between sapphire and tanzanite?
Among the most popular gems in the market, sapphire and tanzanite could not be more different. Sapphire is corundum, with a hardness of 9 on the Mohs scale. It occurs in blue, but also in yellow, pink and green. Most sapphire is heat-treated, but unheated specimens can be found. Tanzanite, on the other hand, is a form of zoisite, with a Mohs hardness of 6.5 to 7.0. Tanzanite colors range from green to purple to blue, but the color most often found in the market is a medium to deep violet blue produced by heat treatment.