metamorphic
Quartz (Quartzite Pebble)
Silicon Dioxide (SiO2)
Hardness: 7 on Mohs scale; Color: Tan to translucent grey; Luster: Vitreous to waxy; Structure: Hexagonal crystal system but often massive/granular; Cleavage: None (conchoidal fracture).
- Hardness
- 7 on Mohs scale
- Color
- Tan to translucent grey
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 7 on Mohs scale; Color: Tan to translucent grey; Luster: Vitreous to waxy; Structure: Hexagonal crystal system but often massive/granular; Cleavage: None (conchoidal fracture).
Formation & geological history
Formed from the metamorphism of quartz-rich sandstone. High heat and pressure Recrystallize the sand grains into a dense, interlocking mosaic of quartz crystals.
Uses & applications
Used in construction as crushed stone, in glass manufacturing, as an abrasive, and frequently as decorative landscaping stone or tumbled pocket stones.
Geological facts
Quartz is the second most abundant mineral in Earth's continental crust. Quartzite is so durable that it frequently outlasts the mountains it was formed in, becoming rounded pebbles in riverbeds.
Field identification & locations
Identify in the field by its inability to be scratched by a steel knife and its lack of reaction to acid. Commonly found in riverbeds, glacial tills, and mountainous regions worldwide.
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