metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale; Color: Grayish-white with brownish streaks; Luster: Dull to waxy; Structure: Granular/Crystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Grayish-white with brownish streaks
- Luster
- Dull to waxy
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale; Color: Grayish-white with brownish streaks; Luster: Dull to waxy; Structure: Granular/Crystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of quartz-rich sandstone under heat and pressure, typically in orogenic belts. This specific specimen has been further shaped by fluvial or glacial erosion into a rounded pebble.
Uses & applications
Construction aggregate, glass manufacture (if high purity), decorative landscaping stones, and sometimes as a material for primitive stone tools.
Geological facts
Quartzite is so hard and chemically resistant that it often forms the caps of ridges and mountains. It is tougher than the sandstone from which it originated because the quartz grains have recrystallized and fused together.
Field identification & locations
Identify by its ability to scratch glass and its granular, sugary appearance when broken. Commonly found in riverbeds, beaches, and glacial till. This specimen shows typical rounding from water transport.
