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Benitoite

Year of discovery: 1907 (California State Gem mine, USA), 1972 (Japan)

Locality list: 3 localities of benitoite

• BaTiSi₃O₉
• [Ba²⁺][Ti⁴⁺][Si₃O₉]^6-

• Class: Benitoite group
• Class: Cyclosilicate (Single ring)
• Insoluble in: HCl
• Fluorescence: Short UV excitation (Blue), Cathodo luminescence

• Ti => Sn: Pabstite
• Ti => Zr: Bazirite
• Ti => Ca₂: Walstromite

• Color: Blue
• Streak: White
• Luster: Vitreous
• Diaphaneity: Transparent-Translucent

• Cleavage: Poor on {1011} (1 plane)
• Hardness: 6-6.5
• Density: 3.7

• System: Hexagonal
• Group: (-6)m2, P(-6)2₂c
• Lattice: a=6.6, c=9.7

Etymology: San Benito county, California state, USA