sedimentary

Tumbled kambaba jasper (likely)

Kambaba jasper, a silica-rich microcrystalline quartz aggregate, commonly containing fossilized cyanobacterial structures and dark green amphibole/pyroxene minerals

AI-generated identification · may be incorrect

Polished, opaque, mottled dark green, cream, and brown; vitreous to waxy luster; Mohs hardness about 6.5–7; no visible cleavage; cryptocrystalline structure. The rounded shape is human-tumbled and polished.

Identified August 11, 2026More sedimentary →

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At a glance

Common name: Tumbled kambaba jasper (likely)
Scientific name: Kambaba jasper, a silica-rich microcrystalline quartz aggregate, commonly containing fossilized cyanobacterial structures and dark green amphibole/pyroxene minerals
Category: sedimentary
Identified: August 11, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a small tumbled stone; $20–$100+ for larger, highly patterned cabochons or display pieces.

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

Formation & geological history

Usually sourced from Madagascar and interpreted as an ancient stromatolitic sedimentary rock, approximately 2.8–3.2 billion years old, later silicified during burial and diagenesis.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary collections; not generally used in construction. Value depends mainly on pattern, polish, and size.

Geological facts

The distinctive orbicular or cellular markings resemble fossil microbial mats, though the exact mineralogy and naming of “kambaba jasper” are variable in the trade.

Field identification & locations

Identify by its opaque green-black swirls or orbicular patches, cream matrix, and glassy polish; distinguish it from green jasper, rhyolite, and serpentine by its characteristic cellular pattern and hardness. Commonly sold from Madagascar.