USA
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
Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Not Available
KNa 2Li(Fe2+ ,Mn2+ ) 2Ti 2Si 8O 24Michael OâDonoghue , Gems, Sixth Edition (2006)
BeAl 2 O 4