metamorphic

Weathered quartz-rich rock, possibly quartzite

Quartzite (mostly SiO₂), with possible iron-oxide staining and minor feldspar or mica

AI-generated identification · may be incorrect

Hardness about 7 Mohs; gray-white to rusty brown, with a dull to glassy luster and granular, interlocking quartz texture. The irregular fracture and apparent lack of prominent cleavage are consistent with quartzite, though the image is insufficient for certainty.

Identified September 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz-rich sandstone is recrystallized during regional metamorphism, commonly during mountain-building events; its age depends on the original sandstone and metamorphic terrain.

Uses & applications

Used as crushed stone, aggregate, building stone, and decorative rock; attractive pieces may be collected but this specimen appears ordinary.

Geological facts

Iron oxides commonly produce the reddish-brown weathering colors. A steel knife should not scratch fresh quartz-rich surfaces, while quartzite typically scratches glass.

Field identification & locations

Common in metamorphic mountain belts worldwide, including the Appalachians, Rocky Mountains, Alps, and Scandinavian Shield. Confirm with a fresh surface, hardness test, and dilute-acid test; professional identification may distinguish it from weathered quartz or sandstone.