Tanzanite is a modern gemstone. The gem was discovered in the shadow of Mt. Kilamanjaro in 1969. It was called zoisite. Zoisite was transparent  and has a naturally reddish brown color. It was found that this gem can be heated to a stable blue to violet, the mesmerizing color of modern Tanzanite. This exquisite form of zoisite was named tanzanite by New York's Tiffany jewelers and it was celebrated as "Gemstone of the 20th Century.” It has now become the second most popular color stone in America, second only to sapphire!.

VARIETY INFORMATION:

MINERAL NAME: Zoisite ,
CHEMICAL COMPOSITION: Ca2Al3(SiO4)3(OH), Calcium Aluminum Silicate Hydroxide.
COLOR: various shades of blue to lavender, deeper along the crystal axis.
INDEX OF REFRACTION: 1.68 - 1.72
HARDNESS: 6.5-7
BIREFRINGENCE: good
CLEAVAGE: perfect in one direction
CRYSTAL SYSTEM: orthorhombic
USES: Gemstone