metamorphic
Quartzite Pebble
Quartzite (SiO2)
Hardness: 7 (Mohs scale), Color: light grey to beige, Luster: vitreous to dull, Crystal structure: granular/crystalline, Cleavage: none (conchoidal fracture), Specific gravity: 2.6-2.7
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Physical properties
Hardness: 7 (Mohs scale), Color: light grey to beige, Luster: vitreous to dull, Crystal structure: granular/crystalline, Cleavage: none (conchoidal fracture), Specific gravity: 2.6-2.7
Formation & geological history
Formed from the metamorphism of quartz-rich sandstone subjected to extreme heat and pressure. This specimen shows significant rounding and smoothing due to fluvial (river) or glacial transport.
Uses & applications
Construction aggregate, landscaping, decorative stone, and historically used for stone tools due to its hardness and durability.
Geological facts
Quartzite is one of the most durable rocks on Earth's surface and is often the last remaining material after softer rocks have eroded away. It is significantly harder and more resistant than the sandstone from which it originated.
Field identification & locations
Identify in the field by its inability to be scratched by steel, its sugary or granular appearance on a fresh break, and its common occurrence as smoothed river rocks or beach pebbles.
