Quartz - Pure Silica Sio2 Material | Hexagonal Prisms, High-temperature Crystallization Varieties, Electrical Properties

'Silica' occurs in several from & when crystallized, occurs as hexagonal Prisms with its heating at 575 C, Quartz (Alpha-Quartz) inverts to high temperature quartz (Beta-Quartz) which Further invert at 87A C to tridymite & this at about 147A C passes into cristobalite & finally to a Silica melt at 171A C to 1756A C The important varities of crystalline quartz are vein quartz, milky, ferruginous, Aventurine quartz cat's eye, rock crystal, amethyst, transparent, besides rock, smoky etc.

COMPOSITION The Crystallized common rock making quartz is pure silica SiO2 but certain massive varieties of silica, such as jasper and opal, which are not crystallized or not apparently so, are of common occurrence and take part in forming rocks, contain in addition more or less combined water, white impurities like clay and oxide of iron are generally present and give them distinctive colours.

PHYSICAL CHARATERS The average specific gravity is 2.65 it's hardness is 7,very important property. Quartz Crystals often slow faces very irregularly developed and are often distorted Occasionally crystals contain small cavities partially or wholly Silica with liquid. Quartz also occurs massive, granular and sometimes stalactite Luster-vitreous occasionally resinous, transparent to opaque, fracture-conchoidal. it is also a refractory material special types of crystalline varieties have electrical properties.