sedimentary

Orbicular jasper (polished pebble)

Silicified volcanic or sedimentary breccia; chiefly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and clay-rich matrix

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque, brown to rust-red with rounded gray, tan, and dark orbicules; waxy to vitreous luster when polished. The circles are silica- or mineral-filled clasts/alteration zones rather than true crystals, so cleavage is absent; specific gravity is about 2.5–2.7.

Identified August 31, 2026More sedimentary →

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At a glance

Common name: Orbicular jasper (polished pebble)
Scientific name: Silicified volcanic or sedimentary breccia; chiefly microcrystalline quartz/chalcedony (SiO₂) with iron-oxide and clay-rich matrix
Category: sedimentary
Identified: August 31, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a small polished pebble; $30–$150+ for unusually vivid, locality-documented slabs or cabochons.

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 fluids replace or cement volcanic fragments, sediments, or vesicles, producing orbicular patterns; exact age and locality cannot be determined from the photograph. Commonly associated with hydrothermal volcanic environments.

Uses & applications

Used for cabochons, beads, carvings, polished display stones, and lapidary specimens; rarely used as aggregate or architectural stone.

Geological facts

Orbicular jasper is a trade name covering several patterned jasper varieties, not one single mineral species. Similar-looking material may be ocean jasper, leopard jasper, or orbicular rhyolite.

Field identification & locations

Identify by its opaque silica-rich body, rounded contrasting orbs, lack of cleavage, and ability to scratch glass; a streak test is usually white. Common sources include Madagascar, Mexico, Australia, and the western United States.