igneous
Rounded river pebble, likely granite or granitic gneiss
Granite-dominated felsic silicate rock; typically quartz, feldspar, and mica
AI-generated identification · may be incorrectFine-to-medium granular texture with muted pink-brown and gray tones, dull granular luster, and no visible cleavage as a whole rock; constituent minerals are approximately Mohs 2–7, with specific gravity around 2.6–2.8.
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Physical properties
Fine-to-medium granular texture with muted pink-brown and gray tones, dull granular luster, and no visible cleavage as a whole rock; constituent minerals are approximately Mohs 2–7, with specific gravity around 2.6–2.8.
Formation & geological history
Likely formed by slow cooling of silica-rich magma deep in the crust, then rounded by prolonged river or beach abrasion; the exact geological age cannot be determined from the photograph.
Uses & applications
Commonly used as landscaping stone, aggregate, paving, and decorative pebble; generally low collector value unless unusually colored or sourced from a notable locality.
Geological facts
Its smooth, near-spherical shape is produced by mechanical weathering and transport, not crystal growth. The granular appearance suggests interlocking mineral grains rather than glass.
Field identification & locations
Look for visible quartz, pink/white feldspar, and dark biotite or hornblende; a fresh broken surface should remain granular and resist scratching by a steel knife. Common in glacial deposits, streambeds, beaches, and gravel deposits worldwide.
