mineral
Quartz
Silicon Dioxide (SiO2)
Hardness of 7 on the Mohs scale, transparent to translucent with a vitreous (glassy) 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, transparent to translucent with a vitreous (glassy) luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.
Formation & geological history
Forms in a wide variety of geological environments including igneous, metamorphic, and sedimentary rocks. Often precipitates from silica-rich hydrothermal solutions or crystallizes directly from cooling magma.
Uses & applications
Used extensively in glassmaking, electronics, oscillators, abrasives, gemstones, and construction materials.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust, surpassed only by feldspar. Its piezoelectric properties make it essential for keeping time in watches.
Field identification & locations
Easily identified in the field by its distinctive crystal shape, high hardness (scratches glass easily), and lack of cleavage. Found worldwide in nearly every geological setting.
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Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Soil with Mineral Detritus and Quartz Fragments
Regolith / Silicate Mineral Aggregate
sedimentary
Limonite / Goethite (Iron Ore Mineral nodule)
FeO(OH)·nH2O / FeO(OH)
mineral
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Schist
Schist
Metamorphic