gemstone

Polished orbicular jasper (probable ocean jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Cream, gray, and brown-black orbicular pattern with a dull-to-waxy polished luster; cryptocrystalline quartz, no visible cleavage, Mohs hardness about 6.5–7, specific gravity roughly 2.5–2.7. The small oval appears tumbled or cabochon-polished.

Identified August 13, 2026More gemstone →

Explore Polished orbicular jasper (probable ocean jasper) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Polished orbicular jasper (probable ocean jasper)
Scientific name: Microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and other mineral inclusions
Category: gemstone
Identified: August 13, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for a small ordinary polished piece; $30–$150+ for vivid, well-defined orbicular patterns or verified locality 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

Forms when silica-rich volcanic fluids cement or replace volcanic rock, with concentric mineral growth producing orbicules; Madagascar ocean jasper is generally Neoproterozoic, approximately 600 million years old. Exact locality cannot be confirmed from the image.

Uses & applications

Used for cabochons, beads, carvings, and decorative stone; attractive pieces commonly serve as inexpensive jewelry or collectibles.

Geological facts

“Ocean jasper” is a trade name applied mainly to orbicular jasper from Madagascar, while jasper is an opaque variety of chalcedony containing abundant impurities.

Field identification & locations

Look for opaque silica, waxy polish, hardness sufficient to scratch glass, and rounded orbicular banding or patches; distinguish it from dyed agate and ceramic by its natural irregular pattern and heft. Common sources include Madagascar, Australia, Mexico, and the western United States.