sedimentary

Weathered jasper pebble (probable red jasper/chert)

Microcrystalline quartz, SiO₂, colored mainly by iron oxides

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque red-brown with cream weathering patches, and a dull to slightly waxy luster. It is cryptocrystalline quartz with no visible cleavage; specific gravity is about 2.6.

Identified August 17, 2026More sedimentary →

Explore Weathered jasper pebble (probable red jasper/chert) in the encyclopedia →

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Physical properties

Formation & geological history

Forms when silica-rich sediment or volcanic material is replaced/cemented by microcrystalline quartz, with iron oxides producing the red color; alteration and weathering created the mottled surface. The specimen’s geological age cannot be determined from the photograph.

Uses & applications

Used as an ornamental and lapidary stone for cabochons, carvings, beads, and tumbled stones; occasionally used decoratively in landscaping. Common pebbles generally have modest value.

Geological facts

The rounded shape indicates transport by water or prolonged abrasion. Cream areas may be weathered silica, lighter host material, or surface coating rather than a separate mineral.

Field identification & locations

Common in stream gravels and weathered silica-rich formations worldwide, including India, Madagascar, Australia, Brazil, and the western United States. A glassy fracture, resistance to scratching by steel, and lack of fizz in dilute acid support jasper; a close identification requires a fresh broken surface or testing.