Southern and central Africa
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
(K,Na) 2(Li,Fe) 3(Zr,Ti,Fe)Si 12O 30Ulrich Henn and Claudio C.
BeAl 2 O 4
Gemmological Tables (2004) More from other references
Transparent, Transparent to nearly opaque