mineral
Tumbled quartz-rich pebble
Likely quartz-bearing chert or jasper; primarily microcrystalline SiO₂
AI-generated identification · may be incorrectSmall rounded, yellow-brown stone with a dull to slightly waxy luster and mottled appearance. Quartz-rich material has Mohs hardness about 6.5–7, no visible cleavage, cryptocrystalline structure, and specific gravity near 2.6; exact identification is limited by the image.
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Physical properties
Small rounded, yellow-brown stone with a dull to slightly waxy luster and mottled appearance. Quartz-rich material has Mohs hardness about 6.5–7, no visible cleavage, cryptocrystalline structure, and specific gravity near 2.6; exact identification is limited by the image.
Formation & geological history
Likely formed from silica-rich sediment or volcanic-derived fluids, then naturally or artificially rounded by abrasion; age and locality cannot be determined visually. Iron oxides probably produce the yellow-brown coloration.
Uses & applications
Commonly collected as a curiosity, tumbled stone, or lapidary material; suitable for cabochons and small decorative objects, but this specimen has little commercial value.
Geological facts
Jasper and chert are varieties of microcrystalline quartz distinguished mainly by opacity, impurities, and texture rather than crystal shape.
Field identification & locations
Look for hardness sufficient to scratch glass, a nonmetallic waxy luster, and absence of fizz in dilute acid; a streak, specific-gravity test, and close inspection can distinguish jasper, chert, and other quartz-rich rocks. Similar material occurs worldwide in sedimentary and volcanic terrains.
