metamorphic

Quartz-rich metamorphic rock, likely quartzite

Quartzite, predominantly crystalline SiO₂, with probable iron-oxide staining and minor feldspar/mica

AI-generated identification · may be incorrect

Hardness about 7 Mohs; gray-white to brown and reddish, with vitreous to dull luster and interlocking quartz grains. Massive, nonfoliated texture; rusty colors likely reflect hematite/goethite coatings or inclusions.

Identified September 4, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when quartz-rich sandstone is recrystallized under heat and pressure during regional or contact metamorphism; individual specimens may be Precambrian to younger, depending on the source formation.

Uses & applications

Used as crushed stone, road aggregate, building stone, countertops, and decorative material; attractive pieces have modest specimen value.

Geological facts

Quartzite commonly breaks across grains rather than around them, producing a conchoidal to irregular fracture and very sharp edges.

Field identification & locations

Identify it by its gritty-to-sugary crystalline texture, lack of obvious bedding, and ability to scratch glass; dilute acid should not noticeably fizz. Common in metamorphic mountain belts worldwide, including the Appalachians, Rocky Mountains, Alps, and India.