Quartz - stock photo

Quartz is a mineral species from the group of silicates, composed of silicon dioxide, or silica. It comes in the form either of large colorless, colored or smoky crystals, or of microscopic crystals with a translucent appearance. Constituting 12% (by mass) of the lithosphere, quartz is the most common mineral (oxygen and silicon are respectively the first and second constituents, in order of importance, of the lithosphere); it is an important component of granite, of which it fills the residual spaces, and of granitic (gneiss, quartzite) and sedimentary (sand, sandstone) metamorphic rocks.