mineral

Polished orbicular jasper (likely kambaba jasper)

Orbicular microcrystalline quartz–feldspar aggregate; commonly sold as Kambaba jasper

AI-generated identification · may be incorrect

Dark green-black polished surface with pale gray-green orbicular markings and a vitreous to waxy luster; opaque, cryptocrystalline, typically Mohs 6.5–7, with no visible cleavage and specific gravity around 2.6–2.8.

Identified August 19, 2026More mineral →

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Physical properties

Formation & geological history

Forms from silica-rich volcanic or sedimentary material that recrystallized into patterned jasper; commercial Kambaba jasper is chiefly associated with Madagascar, though similar orbicular jaspers occur worldwide. Exact geological age depends on locality.

Uses & applications

Used for cabochons, beads, carvings, polished palm stones, and decorative objects; valued mainly as an ornamental lapidary material rather than a gemstone of high rarity.

Geological facts

The circular markings are orbicules produced by contrasting mineral aggregates, often involving quartz, feldspar, chlorite, and amphibole-group minerals. Trade names may be applied inconsistently to visually similar orbicular jaspers.

Field identification & locations

Identify it by its very dark green-black base, pale rounded patterns, opaque body, and ability to take a smooth polish; it should not show glassy transparency or strong cleavage. Common sources include Madagascar, Mexico, Australia, and the United States.