metamorphic

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), with minor feldspar, mica, and iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale gray-white to tan, uneven granular texture, vitreous to dull luster, and no obvious cleavage. Quartz grains appear tightly fused, with dark mica or accessory minerals forming streaks and patches.

Identified September 19, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when quartz-rich sandstone was deeply buried and recrystallized under heat and pressure, commonly during mountain-building events; its exact geological age cannot be determined from the image. The rusty colors likely reflect weathered iron-bearing impurities.

Uses & applications

Used as crushed stone, road aggregate, dimension stone, landscaping rock, and occasionally countertops or decorative specimens; generally limited jewelry value.

Geological facts

Quartzite commonly breaks across grains rather than around them, producing very sharp, irregular fractures. It is typically harder and more resistant to weathering than the sandstone precursor.

Field identification & locations

Identify it by testing whether it scratches ordinary glass and by observing fused quartz grains; sandstone usually shows visible rounded grains and weaker cementation. Common in metamorphic mountain belts worldwide, including the Appalachians, Rocky Mountains, Alps, and Scandinavian mountains.