mineral

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz (SiO₂), commonly with chalcedony and iron-rich alteration minerals

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; pale blue-gray, cream, and brown concentric orbicular patterns; waxy to vitreous luster; cryptocrystalline quartz with no visible cleavage. The piece appears cut and polished.

Identified August 8, 2026More mineral →

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At a glance

Common name: Polished ocean jasper (orbicular jasper)
Scientific name: Microcrystalline quartz (SiO₂), commonly with chalcedony and iron-rich alteration minerals
Category: mineral
Identified: August 8, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a small polished piece; $30–$150+ for unusually vivid patterns, larger cabochons, or collectible Madagascar material.

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

A silica-rich volcanic rock, commonly rhyolitic, later replaced and filled by chalcedony and quartz in cavities and fractures; classic ocean jasper formed in Miocene volcanic rocks of Madagascar. Geological age is roughly 5–20 million years.

Uses & applications

Used for cabochons, beads, carvings, decorative slabs, and lapidary collections; not generally used as a construction stone.

Geological facts

Orbicular patterns result from repeated growth of quartz, feldspar, and iron-oxide-rich layers around nuclei. “Ocean jasper” is a trade name rather than a formally distinct mineral species.

Field identification & locations

Identify it by rounded orbicular or eye-like patterns, opaque-to-translucent chalcedony, and a polished waxy surface; classic material is associated with Madagascar’s northwest coast. Similar orbicular jasper occurs elsewhere, so locality confirmation matters.