mineral
Tumbled gray stone, likely quartz-rich pebble
Uncertain; possibly microcrystalline quartz (chalcedony) or quartzite
AI-generated identification · may be incorrectGray to white, dull-to-waxy luster, rounded by tumbling or natural abrasion, with no visible cleavage; quartz hardness is Mohs 7 and specific gravity about 2.65. The mottled texture may reflect quartz grains or inclusions.
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Physical properties
Gray to white, dull-to-waxy luster, rounded by tumbling or natural abrasion, with no visible cleavage; quartz hardness is Mohs 7 and specific gravity about 2.65. The mottled texture may reflect quartz grains or inclusions.
Formation & geological history
Likely a water-worn or mechanically tumbled siliceous pebble; quartzite forms when sandstone recrystallizes during metamorphism, while chalcedony precipitates from silica-rich fluids. Exact age and locality cannot be determined from the image.
Uses & applications
Common examples are used as decorative stones, landscaping aggregate, lapidary material, and inexpensive specimen pieces; this small, unverified specimen has minimal commercial value.
Geological facts
Quartz-rich stones resist weathering and commonly survive as rounded stream gravels. A glass-scratch test can help confirm quartz, but it may damage the specimen.
Field identification & locations
Look for hardness sufficient to scratch ordinary glass, a white streak, and absence of fizzing in dilute hydrochloric acid; quartzite shows interlocking grains, whereas chalcedony appears uniformly waxy. Common worldwide in river gravels and metamorphic terrains.
