Canada, Russia, Brazil
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
Brown, Red, Red, Yellow, Brown, Violet
Green
Na 4(Ca,Ce) 2(Fe,Mn,Y)ZrSi 8O 22(OH,Cl) 2Ulrich Henn and Claudio C.
BeAl 2 O 4