mineral

Tumbled jasper pebble

Jasper, microcrystalline quartz (SiO₂), commonly iron-oxide stained

AI-generated identification · may be incorrect

Opaque reddish-brown to mustard material with a dull-to-waxy luster and smooth tumbled surface; hardness about 6.5–7 Mohs, no visible cleavage, cryptocrystalline quartz structure, and specific gravity near 2.6.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids replace or cement fine sediment or volcanic material, with iron oxides producing the brown-red color. Formation ages vary widely, from Precambrian to younger volcanic and sedimentary settings.

Uses & applications

Used for beads, cabochons, carvings, décor, and inexpensive lapidary specimens; occasionally used as aggregate or ornamental stone.

Geological facts

The term “jasper” describes an opaque variety of chalcedony or microcrystalline quartz rather than one single mineral species. Its patterns and colors depend mainly on iron, manganese, clay, and included rock fragments.

Field identification & locations

Identify it by opacity, fine-grained texture, waxy surface, and resistance to scratching by a steel knife; quartz or glass should scratch it. Common sources include India, Madagascar, Brazil, Australia, Mexico, and the western United States.