metamorphic
Rounded quartzite pebble
Quartzite, predominantly crystalline SiO₂
AI-generated identification · may be incorrectTypically Mohs hardness 7, white to gray, with a sugary or faintly granular texture and vitreous to dull luster; massive, non-cleavable, and very resistant to scratching. The smooth shape indicates natural water abrasion or tumbling.
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Physical properties
Typically Mohs hardness 7, white to gray, with a sugary or faintly granular texture and vitreous to dull luster; massive, non-cleavable, and very resistant to scratching. The smooth shape indicates natural water abrasion or tumbling.
Formation & geological history
Formed when quartz-rich sandstone was recrystallized under heat and pressure, commonly during mountain-building; its exact geological age cannot be determined from the photograph. Rounded examples are transported in rivers, beaches, or glacial deposits.
Uses & applications
Used as aggregate, road stone, landscaping stone, and building material; attractive pieces are collected or used decoratively, though this small pebble has little commercial value.
Geological facts
Quartzite is generally harder and more durable than its sandstone precursor and commonly fractures irregularly rather than splitting along bedding.
Field identification & locations
Likely identification features are a hard, pale, quartz-rich body and lack of visible pores or cleavage; a steel knife should not scratch it, while quartz can. Common worldwide in quartzite-bearing mountain belts and gravel deposits.
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