Characteristics of Zoisite:

Chemical Name: Calcium aluminum-silicate

Formula: Ca₂Al₃ (OH) Si₃O₁₂ 

Colors: Blue, pink, white, light brown, green, grey

Structure: Orthorhombic

Hardness: 6.5-7

Specific Gravity: 3.2-3.4

Refractive Index: 1.69-1.70

Lustre: Vitreous

Streak: White

Locations: Tanzania, Norway, Italy, Spain, Germany, Scotland, Japan

What is Zoisite? 

The mineral name Zoisite may not be particularly well known, but its gemstone variety, tanzanite, is popular among collectors. Found in lilac-blue to sapphire-blue coloring, it was named after its place of discovery, Tanzania. Tanzanite crystals have strong pleochroism, and show grey, purple or blue depending on the angle from which they are viewed. Another, pink variety is called thulite, from Thule, the name of an ancient island thought to be Norway. Ordinary Zoisite is usually massive and can be carved as a decorative stone, and as beads of cabochons.