gemstone

Polished brecciated jasper pebble

Silicified microcrystalline quartz (SiO₂), commonly iron-oxide-stained jasper

AI-generated identification · may be incorrect

Opaque gray-brown stone with angular pale and dark fragments in a fine matrix; dull to waxy luster and rounded polish. Quartz hardness is about 6.5–7 Mohs, with no visible cleavage and cryptocrystalline structure; density is typically 2.5–2.7.

Identified August 24, 2026More gemstone →

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Physical properties

Formation & geological history

Formed when silica-rich fluids cemented broken rock fragments, often with later iron-oxide staining; the exact geological age cannot be determined from the photograph. Commonly occurs in volcanic or hydrothermal environments and as stream-worn cobbles.

Uses & applications

Used for cabochons, beads, worry stones, carvings, and ornamental objects; it has little industrial value compared with quartz aggregate.

Geological facts

The brecciated pattern results from preexisting fractures being filled and cemented by silica. Jasper varieties are often named by color or locality rather than by a distinct mineral species.

Field identification & locations

Identify it by its opacity, quartz-like hardness, conchoidal edges when broken, and lack of obvious individual crystals; it should scratch glass but not be scratched by a steel knife. Common sources include Brazil, Madagascar, India, Mexico, and the western United States.