mineral
Quartz
Silicon Dioxide (SiO2)
Hardness of 7 on the Mohs scale; color varies (commonly clear, white, milky, pink, yellow, or brownish); vitreous to greasy luster; hexagonal crystal system; conchoidal fracture with no true cleavage; specific gravity of 2.65.
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Physical properties
Hardness of 7 on the Mohs scale; color varies (commonly clear, white, milky, pink, yellow, or brownish); vitreous to greasy luster; hexagonal crystal system; conchoidal fracture with no true cleavage; specific gravity of 2.65.
Formation & geological history
Forms in virtually all geological environments—igneous, metamorphic, and sedimentary rocks. It crystallizes from silica-rich magmas, precipitates out of hydrothermal veins, and persists in sedimentary environments due to its high chemical and physical resistance.
Uses & applications
Widely used in glassmaking, electronics, oscillators, abrasives, gemstones, and ornamental carvings.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust, surpassed only by feldspar. Due to its piezoelectric properties, quartz crystals are used in electronic devices to generate precise frequencies.
Field identification & locations
Easily identified in the field by its characteristic hardness (scratches glass easily), lack of cleavage, and conchoidal fracture. Found worldwide in almost every type of rock formation.
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Arenite (SiO2 based)
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Limonite / Goethite (Iron Ore Mineral nodule)
FeO(OH)·nH2O / FeO(OH)
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Schist
Schist
Metamorphic
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral