mineral

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with orbicular mineral inclusions; mainly SiO₂

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; cream to tan matrix with rounded brown-gray orbs, opaque, waxy to dull luster, and no visible cleavage. The specimen is a small polished or naturally smoothed pebble.

Identified August 29, 2026More mineral →

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Physical properties

Hardness about 6.5–7 Mohs; cream to tan matrix with rounded brown-gray orbs, opaque, waxy to dull luster, and no visible cleavage. The specimen is a small polished or naturally smoothed pebble.

Formation & geological history

Forms when silica-rich volcanic or hydrothermal fluids replace host rock and concentrate contrasting minerals into spherical patterns, commonly in Miocene volcanic settings. The exact age and locality cannot be confirmed from the image.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and decorative objects; it has little industrial value compared with ordinary quartz.

Geological facts

Orbicular patterns are diagnostic but can occur in several jaspers, so “ocean jasper” should be treated as a locality-based trade name unless provenance is known.

Field identification & locations

Look for concentric or radiating orbs in a hard, opaque chalcedonic stone; a steel file should barely scratch it, while glass may be scratched. Ocean jasper is famously associated with Madagascar, whereas orbicular jasper also occurs in Mexico, Australia, and elsewhere.