metamorphic
Tumbled quartz-rich pebble (likely quartzite or vein quartz)
Quartz (SiO₂), possibly quartzite with minor iron-oxide staining
AI-generated identification · may be incorrectHardness about 7 Mohs; pale gray to translucent white with rusty brown inclusions, vitreous luster, and no obvious cleavage. Its rounded shape indicates natural abrasion or tumbling; crystal grains are not resolvable in the image.
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Physical properties
Hardness about 7 Mohs; pale gray to translucent white with rusty brown inclusions, vitreous luster, and no obvious cleavage. Its rounded shape indicates natural abrasion or tumbling; crystal grains are not resolvable in the image.
Formation & geological history
Quartzite forms when quartz-rich sandstone is metamorphosed under heat and pressure, while vein quartz crystallizes from silica-rich fluids; ages vary widely from Precambrian to younger. The smooth surface likely reflects stream wear or deliberate tumbling.
Uses & applications
Common quartz-rich stones are used as landscaping aggregate, abrasives, countertops, and decorative stones; this small piece has mainly educational or collectible value.
Geological facts
Quartz is one of Earth’s most abundant minerals and is resistant to weathering, allowing quartz-rich pebbles to persist after softer minerals erode.
Field identification & locations
Likely identification: scratch-test against ordinary glass (quartz should scratch it), inspect for granular quartzite texture, and check for absence of fizzing with dilute acid. Common in stream gravels and quartz-vein areas worldwide.
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