mineral

Polished ocean jasper (orbicular chalcedony)

Silica-rich microcrystalline quartz, SiO₂; commonly sold as ocean jasper

AI-generated identification · may be incorrect

Polished, mottled sea-green, cream, and pale tan with rounded orb-like patterns and a waxy to vitreous luster. Quartz hardness is about 6.5–7 Mohs; microcrystalline structure, no visible cleavage, specific gravity about 2.6. The image alone cannot confirm the trade identification.

Identified September 27, 2026More mineral →

Explore Polished ocean jasper (orbicular chalcedony) 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

Forms as silica-rich chalcedony in volcanic cavities, with colored mineral inclusions and orbicular growth patterns. Classic ocean jasper comes from late Paleogene to Neogene volcanic rocks on Madagascar’s northwest coast.

Uses & applications

Used for cabochons, beads, carvings, and display pieces; not generally an industrial stone.

Geological facts

“Ocean jasper” is a commercial name rather than a formally defined mineral species; its distinctive orbicular patterns make each polished piece different.

Field identification & locations

Look for rounded, contrasting orb patterns within waxy, opaque-to-translucent chalcedony; the pictured specimen is too small and blurred for definitive identification. Classic material is associated with Madagascar.