metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 on Mohs scale. Color: Milky white. Luster: Dull to vitreous. Crystal structure: Trigonal (microcrystalline). Cleavage: None (conchoidal fracture when broken). Specific gravity: 2.6-2.7.
- Hardness
- 7 on Mohs scale
- Color
- Milky white
- Luster
- Dull to vitreous
Identified More metamorphic →
Explore Quartzite Pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 on Mohs scale. Color: Milky white. Luster: Dull to vitreous. Crystal structure: Trigonal (microcrystalline). Cleavage: None (conchoidal fracture when broken). Specific gravity: 2.6-2.7.
Formation & geological history
Formed from the metamorphism of quartz-rich sandstone subjected to tectonic heat and pressure, recrystallizing the quartz grains. Weathered and rounded into a pebble by fluvial or marine wave action.
Uses & applications
Used primarily for landscaping, decorative gravel, aquarium substrate, and as tumbling media for rock collectors.
Geological facts
Quartzite is so tough that it often survives intense weathering and erosion long after surrounding rocks have broken down, which is why smooth quartzite pebbles are incredibly common on beaches and riverbeds worldwide.
Field identification & locations
Identified in the field by its extreme hardness (cannot be scratched by a steel knife), sugary texture upon close inspection, and smooth, rounded water-worn shape. Found globally in rivers, streams, and coastal beaches.
More like this
