metamorphic
Tumbled quartzite or quartz-rich pebble
Quartzite, composed predominantly of microcrystalline quartz (SiO₂)
AI-generated identification · may be incorrectTypically Mohs hardness 7, white to cream with tan-brown iron-oxide staining, vitreous to dull luster, and no visible cleavage; the rounded shape indicates tumbling or water wear. The image alone cannot distinguish quartzite confidently from chalcedony or another quartz-rich stone.
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Physical properties
Typically Mohs hardness 7, white to cream with tan-brown iron-oxide staining, vitreous to dull luster, and no visible cleavage; the rounded shape indicates tumbling or water wear. The image alone cannot distinguish quartzite confidently from chalcedony or another quartz-rich stone.
Formation & geological history
Quartzite forms when quartz-rich sandstone recrystallizes under heat and pressure, commonly during mountain-building; its exact geological age depends on the source formation. Rounded specimens may come from river gravel, beaches, or commercial tumbling.
Uses & applications
Used as aggregate, building and paving stone, landscaping material, and decorative tumbled stone; generally low jewelry value unless unusually patterned or translucent.
Geological facts
Quartz-rich stones commonly scratch glass and resist weathering. Brown patches are likely iron oxides rather than a distinct mineral variety.
Field identification & locations
Look for granular quartz texture, hardness near 7, conchoidal-to-uneven fracture, and lack of reaction with dilute acid; a streak or scratch test and magnification would improve identification. Common worldwide, especially in quartzite-bearing mountain and gravel regions.
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