Tanzanite
(Ca2Al3(SiO4)(Si2O7)O(OH)) + (Cr,Sr)
Calcium Aluminium Hydroxyl Silicate
Hardness: 6-6.5
Sorosilicate
Orthorhombic System
Violet, blue
Tanzanite
(Ca2Al3(SiO4)(Si2O7)O(OH)) + (Cr,Sr)
Calcium Aluminium Hydroxyl Silicate
Hardness: 6-6.5
Sorosilicate
Orthorhombic System
Violet, blue