Beryl

Mineral composed of beryllium aluminum silicate, Be3Al2(SiO3)6, a commercial source of beryllium. It has long been of interest because several varieties are valued as gemstones. These are aquamarine (pale blue-green); emerald (deep green); heliodor (golden yellow); and morganite (pink). Beryl is a minor constituent of many granitic rocks and associated pegmatite dikes, in gneisses,