metamorphic
Quartzite Pebble (River Pebble)
Quartzite (SiO2)
Hardness: 7 on Mohs scale. Color: yellowish-brown, tan, gray. Luster: dull to waxy/smooth due to water rounding. Structure: microcrystalline, massive structure with no prominent cleavage.
- Hardness
- 7 on Mohs scale
- Color
- yellowish-brown, tan, gray
- Luster
- dull to waxy/smooth due to water rounding
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Physical properties
Hardness: 7 on Mohs scale. Color: yellowish-brown, tan, gray. Luster: dull to waxy/smooth due to water rounding. Structure: microcrystalline, massive structure with no prominent cleavage.
Formation & geological history
Formed from quartz-rich sandstone subjected to high heat and pressure during regional metamorphism, then weathered and tumbled smooth in river systems or along shorelines.
Uses & applications
Commonly used as construction aggregate, decorative landscaping stone, aquascapes, or as a polished river stone specimen.
Geological facts
Quartzite is extremely resistant to chemical weathering and erosion. Smooth river pebbles like this one can be transported hundreds of miles along waterways over thousands of years.
Field identification & locations
Identified by its high hardness (scratches glass easily), smooth rounded shape from stream erosion, and interlocking fine quartz grains. Abundant in regional gravel deposits and river beds around Maryland and the Mid-Atlantic region (such as near 39.4°N, 76.5°W).
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