The mineral beryl is a beryllium aluminium cyclosilicate with the chemical formula Be₃Al₂(SiO₃)₆. The hexagonal crystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Beryl exhibits conchoidal fracture, has a hardness of 7.5–8, a specific gravity of 2.63–2.80. It has a vitreous luster and can be transparent or translucent. Its cleavage is poor basal and its habit is dihexagonal bipyramidal. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, red, and white. The name comes from the Greek beryllos which referred to a precious blue-green color of sea water stone.Beryl: Beryl mineral information and data The term was later adopted for the mineral Beryl more exclusively.Beryl Mineral Data

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