sedimentary

Polished kambaba jasper

Orbicular stromatolitic jasper; microcrystalline quartz (SiO₂) with chlorite/amphibole-rich inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; dark green to black with rounded orbicular patterns, opaque, waxy to vitreous luster, and no visible cleavage. Its rounded holes and swirls are mineral-filled fossil/stromatolite textures rather than crystal faces.

Identified August 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from silica-rich, lithified microbial stromatolite material and associated volcanic sediments, commonly attributed to ancient Precambrian rocks roughly 2.0–3.0 billion years old. Major commercial material comes from Madagascar, with similar orbicular jasper reported elsewhere.

Uses & applications

Used for cabochons, beads, worry stones, carvings, and decorative objects; it has little industrial value as a bulk aggregate. Small polished pieces are mainly collectible or ornamental.

Geological facts

The name “kambaba jasper” is a trade name; “crocodile jasper” is another common label. Geological classification and exact origin are debated for some marketed material.

Field identification & locations

Identify it by its polished dark green-black body and distinctive circular black-green orbs; quartz hardness will resist scratching by a steel knife. Typical polished specimens sell for about $5–$30; larger, attractive carvings may reach $50–$150.