sedimentary
Rounded river pebble (likely fine-grained sandstone or quartzite)
Indeterminate from image; likely quartz-rich sandstone, possibly quartzite
AI-generated identification · may be incorrectSmooth, rounded, tan-gray surface with a dull to slightly waxy luster and no visible crystals. If sandstone, hardness varies with cement (about 3–7 Mohs); quartzite is about 7 Mohs. Grain texture and cleavage are not discernible.
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Physical properties
Smooth, rounded, tan-gray surface with a dull to slightly waxy luster and no visible crystals. If sandstone, hardness varies with cement (about 3–7 Mohs); quartzite is about 7 Mohs. Grain texture and cleavage are not discernible.
Formation & geological history
Water abrasion likely rounded the pebble in a stream or shoreline. Its precise rock type and geological age cannot be established visually.
Uses & applications
Primarily a natural collectible or decorative pebble; similar material may be used in landscaping and aggregate.
Geological facts
A rounded shape indicates prolonged transport or reworking, but does not by itself identify the rock’s composition.
Field identification & locations
Look for visible sand grains, which support sandstone; a uniformly fused, very hard texture suggests quartzite. A scratch test and fresh broken surface would help distinguish them; river pebbles occur worldwide.
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