metamorphic

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with mica or feldspar

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale gray-white, massive and strongly weathered, with a vitreous to dull luster. Interlocking quartz grains and irregular fractures are typical; visible layering or foliation may indicate a quartz-rich schist or gneiss instead.

Identified September 7, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when quartz-rich sandstone was recrystallized under intense heat and pressure during mountain building; its exact geological age cannot be determined from the image. Surface staining and roughness reflect prolonged outdoor weathering.

Uses & applications

Used as crushed stone, road aggregate, building stone, landscaping rock, and occasionally countertops or decorative material; non-gem-quality specimens have little jewelry value.

Geological facts

Quartzite commonly resists weathering better than surrounding rocks and forms ridges or resistant boulders. A steel file generally fails to scratch fresh quartzite, though weathered surfaces may be softer.

Field identification & locations

Common in metamorphic mountain belts worldwide, including the Appalachians, Rocky Mountains, and Precambrian shields. Confirm by testing a fresh surface for abundant interlocking quartz and by checking whether dilute acid produces no fizz.