mineral

Polished brown jasper (probable brecciated jasper)

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

AI-generated identification · may be incorrect

Opaque brown to black, waxy to vitreous luster, with mottled iron staining and possible brecciation; Mohs hardness about 6.5–7, no visible cleavage, conchoidal fracture, and specific gravity near 2.6. The rounded shape indicates tumbling or natural abrasion.

Identified September 14, 2026More mineral →

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Physical properties

Formation & geological history

Jasper forms when silica-rich fluids replace or cement volcanic ash, sediment, or fractured rock, commonly with hematite or goethite producing the brown color. Formation ages vary widely, from Precambrian to younger volcanic and hydrothermal settings.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary specimens; rarely used as a minor decorative stone or aggregate.

Geological facts

Its color and patterns arise mainly from iron oxides rather than distinct large crystals. The specimen may also be iron-rich chert if its texture is especially fine-grained.

Field identification & locations

Identify by its opacity, fine texture, hardness, lack of cleavage, and inability to scratch it with a steel knife; quartz or glass should scratch it. Common sources include India, Madagascar, Brazil, the western United States, and Australia.