Southern and central Africa, Vietnam
USA, Color: blue or violetish blue, colorless, Hardness: 6 6.5, Refractive index: 1.76 1.80, Density: 3.60 3.68, Chemical composition: BaTiSi3O9, Crystal structure: hexagonal, Lustre: vitreous, Origins: San Benito Country, USA. Very rare collectors stone. Found only in San Benito County, California, USA, with specimens over 2 ct. being extremely rare.
Green, Black, Brown
Violet, Blue, Colorless, Blue, pink, White, Colorless