Tanzanite

Tanzanite
 
 Rare mineral , variety of blue Zoisite crystal , intact piece of Tanzanite gemstone .
 Ideal for a collector , this Tanzanite mineral will bring satisfaction and deserve its place in a beautiful collection or showcase .
 
 Origin: Tanzania
 Size: 2cm by 0.9cm by 0.8cm
 Weight: 5gr
 Chemical formula: Ca2Al3 (SiO4) 3OH
 Crystal system: Orthorhombic
 Hardness Mohs scale: 6 - 6.5
 Wikipedia definition: Tanzanite is a blue to purple variety of zoisite discovered in 1967 in Tanzania . It is often found in the form of a transparent gem. It has the same chemical formula as zoisite Ca2 (Al.OH) Al2 (SiO4) 3 but with clearer traces of vanadium.