metamorphic
Quartzite Pebbles
Quartzite (SiO2)
Hardness: 7 (Mohs scale); Color: White, gray, or tan with dark streaks; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (granular); Cleavage: None; Specific gravity: 2.6-2.7
- Hardness
- 7 (Mohs scale)
- Color
- White, gray, or tan with dark streaks
- Luster
- Vitreous to dull
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Physical properties
Hardness: 7 (Mohs scale); Color: White, gray, or tan with dark streaks; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal (granular); Cleavage: None; Specific gravity: 2.6-2.7
Formation & geological history
Formed through the metamorphism of quartz sandstone under high heat and pressure, typically during mountain-building events. This specimen has been further shaped into a rounded pebble by water erosion in a river or beach environment.
Uses & applications
Used in construction as crushed stone, in sandblasting, and as a decorative stone in landscaping or lapidary work.
Geological facts
Quartzite is so tough that it often survives intense weathering better than the rocks surrounding it, leading to its prevalence as river-rolled pebbles. It is one of the most durable rocks on Earth.
Field identification & locations
Identify by its ability to scratch glass and its grainy, sugary texture under a hand lens. Commonly found in riverbeds and glacial till throughout North America and Europe.
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