Rock Identifier
Rounded quartz-rich pebble (Milky quartz or quartzite; predominantly silicon dioxide (SiO₂)) — sedimentary
sedimentary

Rounded quartz-rich pebble

Milky quartz or quartzite; predominantly silicon dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness about 7 Mohs; cream to pale tan, granular, and dull-to-waxy with possible sugary crystalline texture. Quartz has no cleavage, conchoidal fracture, and specific gravity near 2.65; the image is insufficient to distinguish quartz from quartzite confidently.

Identified More sedimentary
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Physical properties

Hardness about 7 Mohs; cream to pale tan, granular, and dull-to-waxy with possible sugary crystalline texture. Quartz has no cleavage, conchoidal fracture, and specific gravity near 2.65; the image is insufficient to distinguish quartz from quartzite confidently.

Formation & geological history

Likely a naturally weathered and water-rounded quartz pebble; if quartzite, it formed when quartz sandstone was metamorphosed and recrystallized. The specimen’s exact geological age and source cannot be determined visually.

Uses & applications

Common quartz pebbles have little commercial value, while quartzite is used as aggregate, landscaping stone, paving, and building material; attractive pieces may be collected or polished.

Geological facts

Quartz is one of Earth’s most abundant minerals and is chemically resistant, allowing it to survive transport as rounded beach- or river-pebbles.

Field identification & locations

Look for glassy fracture, lack of cleavage, and inability to scratch it with a steel knife; it should scratch ordinary glass. A vinegar test is generally uninformative, and a streak test is white.