mineral
Quartz
Silicon Dioxide (SiO2)
Mohs hardness of 7; color ranges from colorless to white, pink, purple, grey; vitreous (glassy) luster; trigonal crystal system; conchoidal fracture with no true cleavage; specific gravity of 2.65.
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Physical properties
Mohs hardness of 7; color ranges from colorless to white, pink, purple, grey; vitreous (glassy) luster; trigonal 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—most commonly crystallizing from silica-rich hydrothermal veins and magmatic pegmatites.
Uses & applications
Used in electronics, oscillators, glassmaking, abrasives, gemstones, and ornamental objects.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust, after feldspar. Its piezoelectric properties make it vital for keeping time in watches.
Field identification & locations
Easily identified by its high hardness (scratches glass), lack of cleavage, and glassy luster. Commonly found worldwide in river gravels, granite pegmatites, and sandstones.
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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
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral