metamorphic

Weathered quartz-rich rock, likely quartzite

Quartzite (mostly SiO₂), possibly iron-stained quartz vein or silicified sandstone

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale gray-white, granular and massive, with rusty red-brown iron-oxide staining. Vitreous to dull luster, no obvious cleavage, and likely high specific gravity around 2.6–2.7.

Identified September 5, 2026More metamorphic →

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Physical properties

Formation & geological history

Quartzite forms when quartz-rich sandstone is recrystallized during metamorphism, commonly during mountain-building; its exact geological age cannot be determined from the photograph. The brown coloration is likely limonite/goethite produced by weathering of iron-bearing minerals or fractures.

Uses & applications

Useful as aggregate, road stone, riprap, landscaping stone, and occasionally dimension stone; attractive pieces may be polished for décor or collected. This specimen appears ordinary rather than gem quality.

Geological facts

Quartzite commonly resists weathering better than surrounding rocks, forming ridges and resistant outcrops. A scratch test against glass can help confirm quartz hardness, though it may damage the specimen.

Field identification & locations

Identify it by its very hard, quartz-granular texture and lack of obvious sand grains or foliation; acid should not fizz. Common occurrences include metamorphic belts worldwide, including the Appalachians, western United States, Brazil, India, and Scandinavia.