metamorphic
Quartzite Pebble
Metamorphic Quartz (SiO2)
Hardness: 7 (Mohs scale), Color: tan to pinkish-brown, Luster: vitreous to waxy (when polished), Crystal Structure: Trigonal, Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: tan to pinkish-brown, Luster: vitreous to waxy (when polished), Crystal Structure: Trigonal, Cleavage: None/Conchoidal fracture, Specific Gravity: 2.65
Formation & geological history
Formed through the metamorphism of quartz sandstone under extreme heat and pressure. This specific specimen appears to be water-worn, smoothed by alluvial or coastal processes across geological time.
Uses & applications
Used primarily in construction aggregate, as a decorative landscaping stone, and occasionally in glass manufacturing or as a polishing abrasive.
Geological facts
Quartzite is one of the hardest and most resistant rocks on Earth's surface. It can often be distinguished from sandstone because it breaks across the grain, rather than around it.
Field identification & locations
Identify in the field by its hardness (it will scratch glass) and its sugary, crystalline texture under a magnifying lens. Commonly found in river beds and ancient shoreline deposits.
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