metamorphic

Rounded river cobbles, likely quartzite and weathered granite

Quartzite (SiO₂) with possible granitic and sandstone companions

AI-generated identification · may be incorrect

Visible stones are water-worn, opaque, and fine- to medium-grained, with pink, tan, gray, and brown coloration. Quartzite has Mohs hardness ~7, vitreous to dull luster, no cleavage, and specific gravity ~2.6; exact identification is limited by the image.

Identified September 21, 2026More metamorphic →

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Physical properties

Formation & geological history

These are likely glacial or river-transported cobbles derived from older igneous and metamorphic bedrock; quartzite forms when quartz-rich sandstone is metamorphosed, commonly during Precambrian to Paleozoic mountain-building. Their rounded shape reflects prolonged abrasion in moving water.

Uses & applications

Used as landscaping stone, decorative aggregate, garden features, and occasionally in construction; attractive quartzite pieces may be polished for décor or jewelry. They have little commercial value unless unusually colorful, patterned, or from a documented locality.

Geological facts

The central pink-orange cobble may be quartzite or weathered granite, while surrounding pieces could include granite, sandstone, or gneiss. A steel knife should not scratch quartzite, though it may scratch softer sandstone.

Field identification & locations

Look for interlocking quartz grains and a sugary texture in quartzite, visible feldspar and dark mica in granite, and foliation in gneiss. Common in streambeds, beaches, and glacial deposits worldwide.