igneous
Weathered quartz-rich river pebble
Likely altered granite or granitic gneiss, composed mainly of quartz, feldspar, and minor mica/iron oxides
AI-generated identification · may be incorrectCoarse-to-fine granular texture, rounded by abrasion, with pale gray, cream, pink, and brown staining; likely Mohs hardness 6–7, vitreous to dull luster, poor or indistinct cleavage at the whole-rock scale, and specific gravity about 2.6–2.7.
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Physical properties
Coarse-to-fine granular texture, rounded by abrasion, with pale gray, cream, pink, and brown staining; likely Mohs hardness 6–7, vitreous to dull luster, poor or indistinct cleavage at the whole-rock scale, and specific gravity about 2.6–2.7.
Formation & geological history
Formed when granitic magma crystallized deep underground, commonly hundreds of millions to billions of years ago, then weathered and transported by water. Brown and reddish areas likely reflect iron-oxide alteration or surface staining.
Uses & applications
Suitable as a decorative pebble, landscaping stone, or lapidary material; generally no significant jewelry value unless it contains attractive mineral banding or can be polished.
Geological facts
Its smooth, rounded form indicates prolonged stream or beach transport. The mixed pink, white, gray, and dark grains are typical of feldspar-quartz-mica rocks rather than a single mineral.
Field identification & locations
Identify it by visible interlocking grains, pale quartz/feldspar content, lack of fossils or layering, and inability to scratch it easily with a steel knife. Common in streams draining continental crust and granitic terrains.
