mineral
Quartz Pebble (Smoky Quartz / Chalcedony)
Silicon Dioxide (SiO2)
Mohs hardness of 7, vitreous to waxy luster, yellowish-brown to smoky brownish-gray color, microcrystalline to cryptocrystalline texture, conchoidal fracture, no distinct cleavage, specific gravity ~2.65.
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Physical properties
Mohs hardness of 7, vitreous to waxy luster, yellowish-brown to smoky brownish-gray color, microcrystalline to cryptocrystalline texture, conchoidal fracture, no distinct cleavage, specific gravity ~2.65.
Formation & geological history
Formed from hydrothermal silica precipitation or weathering of quartz-bearing metamorphic and igneous parent rocks, subsequent water erosion created the rounded pebble shape.
Uses & applications
Commonly used for lapidary practice, tumbled stone crafts, landscaping, and educational geology collections.
Geological facts
Stream-rounded quartz pebbles are among the most resistant minerals on Earth, surviving millions of years of physical and chemical weathering that breaks down other rocks.
Field identification & locations
Identified by its ability to scratch glass easily, waxy/glassy luster, translucent edges, and rounded erosion pattern. Commonly found along riverbeds, beaches, and glacial till deposits.
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