igneous
Weathered quartz-rich pebble, possibly granite or pegmatite
Quartz (SiO₂) with probable feldspar and minor mica/iron-oxide inclusions
AI-generated identification · may be incorrectPale cream-gray, granular and weakly translucent with vitreous to dull luster; likely quartz and feldspar grains, with no obvious cleavage. Estimated hardness 6–7 Mohs and specific gravity about 2.6–2.7; exact properties require testing.
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Physical properties
Pale cream-gray, granular and weakly translucent with vitreous to dull luster; likely quartz and feldspar grains, with no obvious cleavage. Estimated hardness 6–7 Mohs and specific gravity about 2.6–2.7; exact properties require testing.
Formation & geological history
Probably an eroded fragment of felsic igneous rock formed by cooling silica-rich magma, commonly hundreds of millions to billions of years old depending on source terrain. Surface weathering rounded the specimen and altered iron-bearing minerals.
Uses & applications
Ordinary material has little commercial value; comparable rock is used as aggregate, decorative stone, and occasionally as a source rock for quartz or feldspar. Not gem-quality based on the photograph.
Geological facts
The tan coloration may result from iron-oxide staining, while dark flecks could be biotite, hornblende, or weathering pits. A glassy scratch-resistant grain and lack of reaction to dilute acid would support a quartz-rich identification.
Field identification & locations
Common in stream gravels and weathered granite/pegmatite terrains worldwide; inspect fresh surfaces for interlocking quartz and feldspar grains, and test hardness against glass. A precise identification needs a fresh break, streak, magnetism, and mineral tests.
