mineral

Polished ocean jasper / orbicular jasper

Microcrystalline quartz (SiO₂), commonly with chalcedony, feldspar, and iron/manganese oxides

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; pale green, cream, gray, and brown with dark rounded orbicular patches; waxy to vitreous luster and no visible cleavage. The rounded, polished form is human-processed natural silica.

Identified September 15, 2026More mineral →

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

Forms when silica-rich volcanic fluids fill cavities and replace material in altered rhyolitic volcanic rocks; many ocean jasper specimens formed in Oligocene–Miocene volcanic terrain (~5–30 million years ago).

Uses & applications

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

Geological facts

Orbicular patterns result from concentric growth of chalcedony and associated minerals around nuclei, producing eye-like circles and mottling.

Field identification & locations

Identify by its dense feel, glassy/waxy polish, lack of cleavage, and hardness sufficient to scratch glass; classic ocean jasper comes from coastal Madagascar, while similar orbicular jasper occurs worldwide.