mineral

Orbicular jasper (likely ocean jasper)

Silicified volcanic rock composed chiefly of microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray, tan, cream, and rusty colors with circular orbicules; dull to waxy or locally vitreous luster; massive, non-cleaved microcrystalline structure. The pictured piece appears cut or naturally fractured.

Identified August 19, 2026More mineral →

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At a glance

Common name: Orbicular jasper (likely ocean jasper)
Scientific name: Silicified volcanic rock composed chiefly of microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions
Category: mineral
Identified: August 19, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small rough fragment; $20–$150 for attractive polished specimens, depending on pattern, provenance, and finish.

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

Forms when silica-rich volcanic fluids replace or fill cavities in volcanic rock, producing concentric orbicules; many Madagascar ocean-jaspers formed in Jurassic–Cretaceous volcanic settings, though exact locality is uncertain.

Uses & applications

Used for cabochons, beads, carvings, polished slabs, and mineral collecting; too small and irregular for construction use.

Geological facts

Orbicular patterns result from repeated mineral precipitation around nuclei, commonly involving chalcedony, quartz, feldspar, and iron oxides.

Field identification & locations

Identify by its distinctive rounded bull’s-eye patterns, silica hardness, and lack of cleavage; common sources include Madagascar, Mexico, Australia, and the western United States. A definitive identification may require locality or testing.