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.
Russia, Brazil, Tanzania, Madagascar, Zambia, Sri Lanka, Burma, India, Color: color change, from bluish green (daylight) to purple, red or brown (incandescent light), Hardness: 8, Refractive index: 1.74 1.77, Density: 3.68 3.80, Chemical composition: BeAl2O4, Crystal structure: orthorhombic, Origins: Russia, Brazil, Tanzania, Madagascar, Zambia, Sri Lanka, Burma
Violet, Blue, Colorless, Blue, pink, White, Colorless
Green