mineral
Quartz (Milky or Smoky Quartz variety)
Silicon Dioxide (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale. Color: Translucent white to light gray. Luster: Vitreous (glassy) to greasy. Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
- Hardness
- 7 on Mohs scale
- Color
- Translucent white to light gray
- Luster
- Vitreous (glassy) to greasy
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Physical properties
Hardness: 7 on Mohs scale. Color: Translucent white to light gray. Luster: Vitreous (glassy) to greasy. Crystal Structure: Hexagonal (trigonal). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.
Formation & geological history
Formed from cooling magma in igneous rocks or through hydrothermal activity where silica-rich fluids precipitate into veins and cavities. This specific specimen appears to be a water-worn river cobble.
Uses & applications
Used extensively in glassmaking, electronics (piezoelectric properties), abrasives, construction aggregates, and as gemstones or decorative landscaping stones.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. It is chemically very stable and resistant to weathering, which is why it often remains as rounded pebbles in riverbeds long after other minerals have weathered away.
Field identification & locations
Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and characteristic glassy fracture edges. Common in riverbeds, gravel pits, and mountainous regions worldwide.
