mineral

Tumbled jasper pebble

Microcrystalline quartz (chalcedony), chiefly SiO₂, with iron-oxide inclusions

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque, waxy to dull luster, and brown, tan, red, or yellow coloration from iron oxides. It has no visible cleavage and a fine-grained cryptocrystalline structure; the rounded shape indicates tumbling or natural water wear.

Identified August 24, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich groundwater replaces or cements sediment and volcanic material, commonly during the Cenozoic or older hydrothermal episodes. The specimen appears polished/tumbled rather than naturally angular.

Uses & applications

Used for cabochons, beads, carvings, decorative stone, and inexpensive collectibles. It has little industrial use beyond ornamental applications.

Geological facts

Color patterns arise from hematite, goethite, clay, and other impurities; “picture jasper” is a descriptive trade term rather than a single mineral species.

Field identification & locations

Identify it by its opaque fine texture, earthy iron-stained colors, and resistance to scratching by steel; quartz-rich jasper should scratch glass. Common sources include Oregon, Idaho, California, Brazil, India, Madagascar, and Australia.