mineral

Tumbled jasper or iron-rich chert

Microcrystalline quartz (SiO₂), likely colored by iron oxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; dark reddish-brown to gray, opaque, with a dull to slightly waxy luster and no visible cleavage. The rounded shape and smooth surface indicate tumbling or natural water abrasion.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace or cement sediment, while hematite or goethite produces the red-brown coloration; the exact geological age and locality cannot be determined from the photograph. Common settings include volcanic terrains, sedimentary beds, and gravel deposits.

Uses & applications

Used as a lapidary material for cabochons, beads, carvings, and decorative objects; too small or indistinct for construction use.

Geological facts

Jasper and chert are varieties of chalcedony, a microcrystalline form of quartz. Iron-rich varieties may show red, brown, black, or yellow color zoning.

Field identification & locations

A steel file should barely scratch it, whereas glass may be scratched by it; it is nonmetallic and lacks the strong magnetic response of magnetite. Common sources include the western United States, Mexico, Brazil, India, and Australia.