mineral

Polished orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with iron-oxide and feldspar inclusions; commonly called ocean jasper

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray, black, cream, and brown orbicular pattern with a waxy to vitreous luster. Massive, cryptocrystalline structure with no obvious cleavage; specific gravity roughly 2.5–2.7.

Identified August 29, 2026More mineral →

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At a glance

Common name: Polished orbicular jasper (likely ocean jasper)
Scientific name: Silica-rich microcrystalline quartz/chalcedony with iron-oxide and feldspar inclusions; commonly called ocean jasper
Category: mineral
Identified: August 29, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small polished stone; $30–$150+ for unusually vivid, well-patterned cabochons or specimens.

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

Forms when silica-rich volcanic fluids or volcanic rock undergo silicification, producing radiating spherulitic inclusions; Madagascar ocean jasper is mainly Oligocene–Miocene in age. The specimen appears tumbled or polished.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and lapidary collections; not generally an industrial stone.

Geological facts

“Ocean jasper” is a trade name for orbicular jasper varieties, especially those from Madagascar, and its circular patterns are caused by mineral-rich spherulites rather than fossils.

Field identification & locations

Identify by its opaque body, rounded orbicular markings, glassy/waxy polish, and resistance to scratching by steel; quartz or topaz should scratch it, while a steel knife usually will not. Common sources include Madagascar, Mexico, Australia, and Oregon.