igneous and sedimentary
Mixed River Pebbles (including Unakite and Jasper)
Polymineralic geological specimens
Hardness varies between 6 and 7 on the Mohs scale depending on the specific pebble; colors include green, pink, brown, and yellow; luster ranges from dull to waxy; compact cryptocrystalline and phaneritic crystal structures.
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Physical properties
Hardness varies between 6 and 7 on the Mohs scale depending on the specific pebble; colors include green, pink, brown, and yellow; luster ranges from dull to waxy; compact cryptocrystalline and phaneritic crystal structures.
Formation & geological history
Formed through various geological processes including igneous crystallization (for the porphyritic granite/unakite) and sedimentary precipitation (for the chert/jasper), subsequently weathered, transported, and rounded by water action in riverbeds.
Uses & applications
Used in decorative landscaping, tumbling, lapidary arts, and rock collecting.
Geological facts
Water-worn pebbles like these are smoothed by tumbling against other rocks in high-energy river environments over thousands or millions of years.
Field identification & locations
Commonly found in stream beds, glacial tills, and beaches. Collectors identify them by their smooth, rounded surfaces and distinct mineral patterns revealed through weathering.
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igneous
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mineral
Botryoidal Chalcedony
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Mineral
Greenstone (Greywacke or Nephrite Jade variant)
Metamorphosed mafic igneous or sedimentary rock (e.g., Actinolite-Chlorite Schist)
metamorphic
Tumbled Agate
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gemstone
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mineral