Chemical composition: Be3Al, Si () lg; small amount of Na, Rb and Li may substitute for be; H., 0 and CO, may occur within rings.
Physical properties:
(i) Form: Hexagonal prism or columnar aggregates.
(ii) Colour: Colourless, bluish-green, emerald-green, golden-yellow, pink, white.
ADVERTISEMENTS:
(iii) Lustre: Vitreous.
(iv) Streak: White.
(v) Hardness: 7-8.
(vi) Cleavage: Indistinct.
ADVERTISEMENTS:
(vii) Fracture: Conchoidal to uneven.
(viii) Specific gravity: 2.7 – 2.9.
(ix) Diaphaneity: Transparent to translucent.
Use:
ADVERTISEMENTS:
Beryl is the major source of beryllium, which is made alloy with copper resulting in increase of hardness, tensile strength and fatigue resistance of copper. Emerald, transparent and emerald-green (pale green) and aquamarine, transparent pale blue varieties of beryl are used as gemstones.