gemstone

Polished brecciated jasper

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide and possibly clay/mineral inclusions

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque, brown to honey-yellow with dark red-brown and gray patches; vitreous to waxy luster and no visible cleavage. This rounded, polished specimen shows brecciation and crystalline druzy-like quartz pockets.

Identified September 10, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills fractures and cavities, cementing fragments of earlier volcanic or sedimentary material; iron oxides create the brown, red, and yellow colors. Jasper deposits are generally associated with volcanic and hydrothermal environments of varied ages.

Uses & applications

Used for cabochons, carvings, beads, bookends, and ornamental objects; durable polished pieces are popular among collectors.

Geological facts

Jasper is a variety of opaque chalcedony rather than a single mineral species. Its patterns and colors result mainly from impurities, especially hematite, goethite, and other iron minerals.

Field identification & locations

Identify it by its opaque appearance, fine-grained texture, glassy/waxy polish, conchoidal fracture, and inability to scratch with a steel knife; it should not react with dilute acid. Common sources include Oregon, California, Mexico, Madagascar, Brazil, and Australia.