Minerals and Metals in Ancient India v2.c47.176
Minerals and Metals in Ancient India v2.c47.176
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v2.c47.176
*Tourmaline* : Usually bluish-black, vertically striated prismatic, vitreous to resinous luster. May be of different colours — black, blue, green, red — due to impurities. Birefringent, pyro-electric.