TANZANITE CHARACTERISTICS Origin of the name: From its country “Tanzania” and discovered in 1954. Chemical Composition: Calcium aluminum silicate, Ca2Al3(O/OH/SiO4/SiO7). Hardness: Between 6.5 and 7. Crystal system : Orthorhombic Deposits: Tanzania. Color(s): Blue, purplish blue, bluish violet. History and Legends: Lithotherapy Properties: Physical Properties: Signs of the zodiac: Chinese signs: Chakra: