igneous
Likely quartz-rich pebble
Quartz-bearing granite, granitic gneiss, or quartzite (indeterminate from photo)
AI-generated identification · may be incorrectSmall rounded gray-tan pebble with a granular, weakly glinting surface; likely quartz and feldspar, with possible mica. Quartz has Mohs hardness 7, vitreous luster, no cleavage, and a hexagonal crystal structure; the specimen’s overall hardness and density cannot be confirmed visually.
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Physical properties
Small rounded gray-tan pebble with a granular, weakly glinting surface; likely quartz and feldspar, with possible mica. Quartz has Mohs hardness 7, vitreous luster, no cleavage, and a hexagonal crystal structure; the specimen’s overall hardness and density cannot be confirmed visually.
Formation & geological history
Probably weathered from a granitic or metamorphic source and rounded by stream or shoreline transport; its exact geological age and formation environment are unknown.
Uses & applications
Common material for aggregate, landscaping, and road construction; this ordinary pebble has little jewelry or industrial value.
Geological facts
The pale translucent grains may be quartz, while cream or pink grains could be feldspar. A fresh broken surface would distinguish interlocking granite from more uniformly quartz-rich quartzite.
Field identification & locations
Look for visible interlocking grains, quartz’s glassy appearance, and resistance to scratching; test with a steel file and inspect a fresh surface with a hand lens. Common worldwide in river gravels and glacial deposits.
