sedimentary

Polished ocean jasper (orbicular jasper)

Microcrystalline quartz/chalcedony (SiO₂) with iron-rich and volcanic inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; dark gray to brown with cream, yellow, and orange orbicular patterns; vitreous to waxy luster; no visible cleavage and conchoidal fracture. The triangular piece is polished and likely cut from lapidary rough.

Identified September 4, 2026More sedimentary →

Explore Polished ocean jasper (orbicular 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

A silica-rich volcanic or sedimentary material formed through silicification and development of spherical mineral inclusions, generally associated with Cenozoic volcanic terrains. Classic ocean jasper comes from Miocene-age flows near Madagascar.

Uses & applications

Used for cabochons, carvings, beads, polished display pieces, and collector specimens; it has minor ornamental value rather than industrial importance.

Geological facts

“Ocean jasper” is a trade name, not a single strictly defined mineral species; orbicular patterns commonly reflect concentric growth of chalcedony, quartz, and iron oxides.

Field identification & locations

Identify it by its opaque body, rounded contrasting orbs, silica-like hardness, and lack of cleavage; genuine Madagascar material is commonly orbicular and multicolored. Similar patterned jasper and rhyolite can look alike.