Beryl

Description

Beryl is a mineral composed of beryllium aluminium cyclosilicate with the chemical formula Be₃Al₂Si₆O₁₈. Well-known varieties of beryl include emerald and aquamarine. Naturally occurring, hexagonal crystals of beryl can be up to several meters in size, but terminated crystals are relatively rare. https://www.mindat.org/min-819.html