metamorphic

Polished brecciated jasper

Brecciated jasper (microcrystalline quartz, SiO₂), likely iron-stained chalcedony matrix

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque brown, cream, and reddish material with a polished/worn luster. It has a cryptocrystalline quartz structure, no visible cleavage, and typical specific gravity around 2.5–2.7.

Identified September 5, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when silica-rich sediment or volcanic material is fractured, then the cracks are filled and cemented by quartz/chalcedony, often with iron oxides producing red-brown colors. The exact age cannot be determined from the photograph; deposits range from Precambrian to younger volcanic settings.

Uses & applications

Used for cabochons, beads, carvings, bookends, and decorative stone; occasionally as aggregate or architectural accent. Its value is mainly ornamental and depends on pattern, polish, and size.

Geological facts

The angular cream vein network represents brecciation and silica cementation, while dark red-brown coloration commonly reflects hematite or goethite. Jasper is a variety of opaque chalcedony rather than a single mineral species.

Field identification & locations

Identify it by its opaque, patterned quartz-rich body, glassy polish, and inability to scratch with a steel knife; it should scratch glass. Common sources include India, Madagascar, Brazil, Mexico, and the western United States.