igneous
Rounded gray pebble, likely granite or granodiorite
Probable granite/granodiorite; exact identification requires close examination of its mineral grains
AI-generated identification · may be incorrectFine- to medium-grained, gray and speckled, with a dull to slightly granular luster; likely composed mainly of quartz, feldspar, and dark mica or amphibole. Typical hardness is about 6–7 Mohs; individual mineral grains have distinct crystal structures and cleavage.
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Physical properties
Fine- to medium-grained, gray and speckled, with a dull to slightly granular luster; likely composed mainly of quartz, feldspar, and dark mica or amphibole. Typical hardness is about 6–7 Mohs; individual mineral grains have distinct crystal structures and cleavage.
Formation & geological history
If granitic, it formed by slow cooling of silica-rich magma underground, commonly during Precambrian or later geologic time. Its rounded shape likely developed through prolonged abrasion and weathering in a river or on a beach.
Uses & applications
Similar stone is used as aggregate, paving, and landscaping material; this pebble is suitable for display or collecting.
Geological facts
The smooth, oval shape is consistent with natural transport and abrasion, rather than identifying a particular rock type.
Field identification & locations
Look for visible interlocking quartz and feldspar grains and test hardness only on an inconspicuous spot; the image alone cannot confirm granite. Rounded pebbles occur in river gravels and coastal deposits worldwide.
