igneous
Rounded granitic pebble
Granite, likely quartz–feldspar–biotite aggregate
AI-generated identification · may be incorrectLight gray, fine- to medium-grained, granular texture with dark biotite or amphibole flecks; typically Mohs 6–7, vitreous to dull luster, no prominent cleavage as a rock, and specific gravity about 2.6–2.8.
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Physical properties
Light gray, fine- to medium-grained, granular texture with dark biotite or amphibole flecks; typically Mohs 6–7, vitreous to dull luster, no prominent cleavage as a rock, and specific gravity about 2.6–2.8.
Formation & geological history
Formed when silica-rich magma slowly crystallized deep underground, probably during an ancient continental plutonic event; the pebble’s smooth shape results from later stream or wave abrasion. Exact age cannot be determined from the photograph.
Uses & applications
Used widely as crushed stone, aggregate, building stone, monuments, and landscaping material; this small rounded specimen has mainly educational or decorative value.
Geological facts
Visible grains and contrasting dark minerals are consistent with granite, though granodiorite or a weathered gneiss fragment is also possible from an image alone.
Field identification & locations
Look for interlocking pale quartz and feldspar grains with scattered black mica or amphibole; common in continental uplands and glacial or beach gravels. A hand lens, streak, and fresh broken surface improve identification.
