sedimentary

Polished Kambaba jasper (orbicular jasper)

Orbicular microcrystalline quartz, commonly sold as Kambaba jasper; typically quartz/chalcedony with dark green to black amphibole or other inclusions

AI-generated identification · may be incorrect

Polished, glossy surface with rounded dark orbicular patterns and blue-gray highlights. Quartz-rich material is about Mohs 6.5–7; exact mineral mix and specific gravity vary.

Identified September 25, 2026More sedimentary →

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At a glance

Common name: Polished Kambaba jasper (orbicular jasper)
Scientific name: Orbicular microcrystalline quartz, commonly sold as Kambaba jasper; typically quartz/chalcedony with dark green to black amphibole or other inclusions
Category: sedimentary
Identified: September 25, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small polished piece; larger or finely patterned carvings may cost more.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Polished, glossy surface with rounded dark orbicular patterns and blue-gray highlights. Quartz-rich material is about Mohs 6.5–7; exact mineral mix and specific gravity vary.

Formation & geological history

Orbicular textures form as mineral-rich fluids or fine silica-rich material develop rounded patterns during rock formation and alteration. Kambaba jasper is commonly attributed to altered volcanic rocks in Madagascar, often described as Precambrian, though the trade name is applied inconsistently.

Uses & applications

Used for cabochons, beads, carvings, and decorative collectibles; not typically used as a major construction stone.

Geological facts

“Kambaba jasper” is a lapidary trade name, and many pieces sold under it are orbicular rocks rather than true jasper composed solely of quartz.

Field identification & locations

Look for rounded, eye-like dark orbs in a green-black matrix; polished specimens can be difficult to distinguish from other orbicular jasper or rhyolite varieties. Commonly marketed from Madagascar.