metamorphic

Weathered quartz-rich rock, likely quartzite

Quartzite (mostly microcrystalline quartz, SiO₂), possibly iron-oxide-stained sandstone

AI-generated identification · may be incorrect

Hardness about 7 Mohs; mottled gray-brown with rusty red-orange staining, dull to slightly vitreous luster, and no obvious cleavage. The rounded form and granular-looking fracture are consistent with abrasion and quartz-rich composition.

Identified September 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely metamorphosed quartz sandstone, recrystallized under heat and pressure during mountain-building; its precise geological age and locality cannot be determined from the photograph.

Uses & applications

Quartzite is used as crushed stone, aggregate, building stone, and occasionally decorative material; this small weathered piece has minimal commercial value.

Geological facts

Iron oxides such as hematite or goethite commonly produce the red-orange coloration. A true quartzite typically breaks across quartz grains rather than around them.

Field identification & locations

Common in metamorphic terrains and river or glacial gravels worldwide. Test with a steel knife or glass: quartzite should resist scratching and scratch glass; dilute acid should show no reaction unless carbonate minerals are present.