metamorphic
Quartz (Quartzite or Quartz Pebble)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale. Color: Translucent white, gray, with cloudy inclusions. Luster: Vitreous to greasy. Crystal structure: Trigonal/Hexagonal. Cleavage: None (conchoidal fracture). Specific gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Translucent white, gray, with cloudy inclusions
- Luster
- Vitreous to greasy
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Physical properties
Hardness: 7 on Mohs scale. Color: Translucent white, gray, with cloudy inclusions. 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 or through erosion of quartz veins. This specific specimen appears to be a river-tumbled or polished pebble, formed over millions of years by mechanical weathering and water transport.
Uses & applications
Quartz is used extensively in glassmaking, electronics (oscillators), and as an abrasive. Polished pebbles like this one are commonly used in home decor, landscaping, and as pocket stones.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. It is chemically stable and resistant to weathering, which is why it often survives as rounded pebbles in riverbeds.
Field identification & locations
Can be identified in the field by its ability to scratch glass, its lack of cleavage, and its typical translucent appearance. It is ubiquitous in river systems and coastal areas worldwide.
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