Emerald

Emerald is the green variety of beryl with a chemical composition of Be3Al2Si6 O18. This beryllium aluminium silicate frequently has some sodium, lithium, and cesium included in the mineral ( Chesterman, 1979, p.560). The luster is vitreous and beryl has a colorless streak. The hardness is 7.5-8 and specific gravity ranges from 2.66 to 2.92. Beryl's fracture is uneven to conchoidal and the