metamorphic

Weathered quartz-rich rock, likely quartzite

Quartzite (mostly microcrystalline SiO₂), possibly quartz-rich sandstone

AI-generated identification · may be incorrect

Hardness about 7 Mohs; off-white to gray-brown with rusty iron staining, granular texture, and dull to sugary/vitreous luster. Quartzite has interlocking quartz grains and no prominent cleavage; the rounded shape indicates water or abrasion weathering.

Identified September 7, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz-rich sandstone is metamorphosed under heat and pressure, commonly during mountain building; its exact geological age cannot be determined from the image. The surface appears naturally weathered and rounded.

Uses & applications

Durable quartzite is used for aggregate, road stone, building slabs, flooring, and decorative stone; attractive pieces may be collected but this specimen has little commercial gemstone value.

Geological facts

Quartzite is generally more resistant to weathering than its parent sandstone and commonly preserves iron-oxide bands or stains. A true quartzite breaks across grains rather than around them.

Field identification & locations

Common in metamorphic mountain belts and river gravels. Test with a steel file or glass: it should resist scratching and may scratch glass; dilute acid should produce no fizz unless carbonate cement is present.