metamorphic
Quartz / Quartzite
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: White to milky translucent with yellowish iron staining; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- White to milky translucent with yellowish iron staining
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 7 on Mohs scale; Color: White to milky translucent with yellowish iron staining; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under high heat and pressure, or as a vein deposit from hydrothermal fluids. This specimen appears water-worn, likely found in a riverbed or coastal environment.
Uses & applications
Used as an abrasive, in glass manufacturing, as a construction aggregate, and in landscaping. Pure specimens are used for electronics and jewelry.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which has Slavic origins meaning 'hard'.
Field identification & locations
Identify in the field by its hardness (it will scratch glass) and lack of cleavage. It is commonly found in river beds, beaches, and mountain trails globally. Its rounded shape suggests long-term transport by water.
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