Minerals and Metals in Ancient India v2.c47.17
Minerals and Metals in Ancient India v2.c47.17
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v2.c47.17
**Beryl** : Be₃Al₂(SiO₃)₆ sometimes a little Na, Li or Cs replacing Be. Hardness 7.5-8.0. Several varieties. Emerald bright green contains little chromium. Pure beryl hexagonal prism, pale green.