Rock Identifier
Tumbled jasper (likely ocean or picture jasper) (Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and clay inclusions) — mineral
mineral

Tumbled jasper (likely ocean or picture jasper)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and clay inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque mustard-yellow to brown with mottled, fine-grained patterns and a waxy-to-dull luster. It has no visible cleavage, conchoidal fracture, and moderate specific gravity around 2.6.

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Physical properties

Hardness about 6.5–7 Mohs; opaque mustard-yellow to brown with mottled, fine-grained patterns and a waxy-to-dull luster. It has no visible cleavage, conchoidal fracture, and moderate specific gravity around 2.6.

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic ash, sediments, or other rock, with iron oxides producing the yellow-brown color. Its exact geological age cannot be determined from the photograph and varies by deposit.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and ornamental objects; common tumbled pieces generally have modest commercial value.

Geological facts

Jasper is an opaque variety of chalcedony and quartz rather than a single mineral species. Color zoning and abstract patterns result from iron minerals, clay, and other trapped impurities.

Field identification & locations

The rounded, polished shape indicates human tumbling; a glassy surface, very high hardness, and inability to scratch it with a steel knife support jasper identification. Common sources include Oregon, Idaho, Utah, Madagascar, Brazil, and Australia.