sedimentary
Quartz (Gravel Pebble)
Silicon Dioxide (SiO2)
Hardness: 7; Color: Translucent tan to brown; Luster: Vitreous to dull; Crystal Structure: Trigonal (though warn as river-worn pebble); Specific Gravity: 2.65
- Hardness
- 7
- Color
- Translucent tan to brown
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7; Color: Translucent tan to brown; Luster: Vitreous to dull; Crystal Structure: Trigonal (though warn as river-worn pebble); Specific Gravity: 2.65
Formation & geological history
Formed from the weathering and aquatic transport of larger igneous or metamorphic quartz veins; polished over time by river or coastal erosion.
Uses & applications
Common gravel is used in landscaping, concrete aggregate, and road construction; high-quality quartz is used in glassmaking and electronics.
Geological facts
Quartz is the most abundant mineral in the Earth's continental crust. These rounded pebbles are often called 'river rocks' and can survive millions of years of transit due to their high hardness.
Field identification & locations
Identify by its hardness (cannot be scratched by a steel knife) and lack of cleavage. Commonly found in riverbeds, glacial deposits, and beaches.
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