rock

Orbicular jasper (ocean jasper)

Silicified orbicular rhyolite; predominantly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide-rich inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque cream, red, and brown orbicules, with a waxy to vitreous luster and no obvious cleavage. The concentric spots are silica-rich spherulites and iron-oxide/mineral inclusions.

Identified September 7, 2026More rock →

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At a glance

Common name: Orbicular jasper (ocean jasper)
Scientific name: Silicified orbicular rhyolite; predominantly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide-rich inclusions
Category: rock
Identified: September 7, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small tumbled or polished piece; $30–$150+ for attractive cabochons or unusually vivid, well-patterned specimens.

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

A volcanic silica-rich rock formed when rhyolitic lava cooled and devitrified, producing orbicular textures later cemented or replaced by chalcedony. Classic ocean jasper formed in Madagascar, mainly in Miocene-age volcanic rocks (roughly 5–23 million years old).

Uses & applications

Used for cabochons, polished stones, carvings, beads, and decorative objects; valued primarily as a lapidary and collector material rather than construction stone.

Geological facts

Its “eye” patterns vary greatly from specimen to specimen, and many marketed examples are more accurately called orbicular jasper or orbicular rhyolite than true ocean jasper.

Field identification & locations

Identify it by the distinctive rounded, concentric red-and-cream orbs in a silica-rich matrix, high hardness, and inability to scratch with a steel knife easily. Common sources include Madagascar; similar orbicular jaspers occur in Oregon, Mexico, and Australia.