Hardness 6.5 specific gravity 3.15-3.38
Refractive index 1.69-1.70 birefringence 0.006-13
Wear: poor durability, fragile and fragile
Tanzanite is a transparent blue variety of mineral zoisite. It was found in Tanzania in 1967. Although its hardness is low, it is popular because of its color comparable to sapphire.
Tanzanite is violet to blue because it contains vanadium (V) and chromium (CR). If it contains vanadium, it will be blue. If it contains chromium, it will be violet.
Tanzanite is a December birthstone.
History of human understanding of Tanzanite
In 1962, the blue "zoisite" was first found near Mount Kilimanjaro, but it was not until 1967 that the mining began. Tiffany & Co., an American jewelry company, named the gemstone "Tanzanite" from Tanzania, where it was found, and first extended it to the U.S. and global markets.
The color of Tanzanite
Tanzanite has a strong natural trichromatic property. It can present three different colors on a gem, but the yellow and brown tones will affect the original body color.
Natural blue Tanzanite is very rare. Most of the Tanzanite on the market are heated. After heating at 400-500 ℃, the yellow and brown tones in Tanzanite fade, and the blue becomes deeper, reaching a higher gem color.
Tanzanite belongs to orthorhombic system and biaxial crystal.
Wearing and preservation of Tanzanite
Tanzanite has a Mohs hardness of only 6.5, which is softer than the dust in the air. If exposed to the air for a long time, the surface gloss may be reduced. Therefore, tanzanite is more suitable for decoration rings than engagement rings.
It is not allowed to carry out ultrasonic and steam cleaning. It can only be cleaned with warm soapy water and dried with dry cloth after cleaning.