metamorphic

Quartz-rich metamorphic rock, likely milky quartzite

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

AI-generated identification · may be incorrect

Hardness about 7 Mohs; white to gray and cream with rusty yellow-brown patches, vitreous to waxy luster, massive granular texture, and no obvious cleavage. The rounded specimen appears naturally weathered or waterworn.

Identified September 5, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when quartz-rich sandstone was recrystallized under heat and pressure, typically during regional metamorphism; its exact geologic age cannot be determined from the image. Common in metamorphic belts and resistant stream or glacial gravels.

Uses & applications

Used as crushed stone, aggregate, building stone, landscaping material, and occasionally as decorative or lapidary material. This specimen has modest collector value unless provenance or unusually attractive veining is established.

Geological facts

Quartzite is commonly mistaken for quartz, but its interlocking granular texture and rock-like mass distinguish it from a single crystal. Iron oxides produce the cream, yellow, and brown coloration.

Field identification & locations

In the field, it scratches glass, resists a steel blade, and typically lacks acid reaction; inspect a fresh surface for fused quartz grains. Common sources include the Appalachians, Rocky Mountains, Precambrian shields, and metamorphic terrains worldwide.