Nat Zoisite

Nat Zoisite from Tanzania 1.25 CT 

Zoisite is a calcium aluminum hydroxy sorosilicate mineral that occurs in a wide variety of colors, including colorless, green, brown, pink, yellow, and blue. It is most famous for its transparent blue-violet gemstone variety, Tanzanite, and the opaque green-and-red variety known as Ruby in Zoisite. 

Key Mineral Facts

• • Chemical Formula: Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)
  • Crystal System: Orthorhombic
  • Hardness: 6.0 to 7.0 on the Mohs scale

• Luster: Vitreous (glassy), sometimes pearly on cleavage surfaces
• Discovery: Discovered in 1805 in the Saualpe Mountains of Austria and named after the Austrian mineral collector Sigmund Zois von Edelstein. 

• Tanzanite: Found exclusively in Tanzania, this transparent purplish-blue stone gets its color from trace amounts of vanadium. It is highly prized as a precious gemstone. 
• Ruby in Zoisite (Anyolite): An opaque, coarse-grained material where deep red or pink corundum (ruby) crystals are embedded in a green zoisite and black pargasite matrix. It is widely used for carvings and decorative items. 
• Thulite: An opaque, massive pink-to-red variety of zoisite, often used for beads and ornamental objects. 
• "Fancy" Zoisite: Transparent unheated zoisites also appear in pastel colors such as yellow, green, and pink, and are frequently collected by gemstone enthusiasts.