metamorphic

Tumbled quartzite pebble

Quartzite; predominantly microcrystalline quartz (SiO₂)

AI-generated identification · may be incorrect

Hardness about 7 Mohs; cream to pale yellow, fine-grained, and subtly translucent with a dull to vitreous polish. Quartzite has no cleavage, uneven fracture, and typically high durability; the rounded shape indicates tumbling or water wear.

Identified September 18, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when quartz-rich sandstone recrystallizes under heat and pressure, commonly during regional metamorphism. Its exact geological age and locality cannot be determined from the photograph.

Uses & applications

Used as durable aggregate, decorative stone, landscaping material, and occasionally as a lapidary or display specimen; this common tumbled piece has little jewelry value.

Geological facts

The specimen may resemble chalcedony, marble, or weathered quartz, but its granular texture and very high hardness favor quartzite. A steel blade should not scratch it; quartzite can scratch ordinary glass.

Field identification & locations

Common in metamorphic belts and river gravels worldwide, especially near quartz-rich sandstone formations. Confirm with a hardness test, close inspection for fused quartz grains, and dilute acid testing to distinguish it from calcite marble.