gemstone

Polished orbicular jasper (likely ocean jasper)

Silicified microcrystalline quartz/chalcedony with iron-oxide and other mineral inclusions; SiO₂

AI-generated identification · may be incorrect

Opaque, highly polished, cream-green matrix with red, orange, brown, and dark orbicular patches. Quartz hardness is about 6.5–7 Mohs; vitreous to waxy luster; no visible cleavage; cryptocrystalline structure. The rounded shape is human-tumbled or carved.

Identified September 21, 2026More gemstone →

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

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed when silica-rich fluids silicified volcanic rock, preserving contrasting mineral-rich spherules; later weathering and polishing exposed the pattern. Classic Madagascar ocean jasper is Oligocene–Miocene (~23–5 million years old), though visually similar orbicular jasper occurs elsewhere.

Uses & applications

Used for cabochons, spheres, palm stones, beads, and decorative objects. Value depends strongly on pattern, polish, color, and provenance.

Geological facts

The red colors commonly reflect hematite or related iron oxides; green areas may contain chlorite or other alteration minerals. “Ocean jasper” is a trade name, not a single formally defined mineral species.

Field identification & locations

Identify by its opaque chalcedony-like body, concentric orbicules, and strong polish; a glassy uniform appearance or bubbles would suggest imitation. At 43.2°N, 79.8°W, this is most likely a purchased/imported polished specimen rather than locally formed bedrock.