The most prized variety of zoisite, tanzanite has become extremely popular in the past few years because of its beautiful color and good luster, which are confused with, blue sapphire. Tanzanite has a strong pleochroism due to which it shows purple, blue or gray depending on the angle from which it is viewed. The actual color of tanzanite when mined is light grayish or brownish blue with yellow and brown tints but when it is heated then all other colors or shades vanish whereas the blue deepens.

Locations:

Tanzanite is found only in Tanzania, due to which it got its name. The only known source is a five square mile hilltop at Merelani, ten miles south of the Kilimanjaro International Airport.

Chemical Composition: Calcium Aluminum Silicate
Crystal Structure: Orthorhombic
Hardness: 6.5
Specific Gravity: 3.35
Refractive Index: 1.69-1.70
Colors: Sapphire blue, amethyst blue and violet.
Luster: Vitreous

Astrological Relevance:

Sunstone feldspar is considered to be one of the birthstones for the month of December, which covers two zodiac signs: Sagittarius (November 21 To December 21) and Capricorn (December 21 To January 21).