Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. It constitutes an important part of most igneous rocks. It has a trigonal crystal structure composed of silicon–oxygen tetrahedra (silicon dioxide, SiO2). Quartz forms six-sided crystals with pyramidal terminations. Has hardness 7 on the Mohs scale. Brazil is well known for its deposits of quartz crystals. The largest documented single crystal of quartz was found near Itaporé, Goiás, Brazil measuring approximately 6.1×1.5×1.5 m and weighing more than 44 tonnes.
Quartz has many industrial uses, for example, ceramic, foundry use, use in sandblasting and also for the manufacture of products such as silicon, ferro silicon, glass, fiber glass, silicon chips, optical fibers, among other.
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