sedimentary

Polished orbicular jasper

Silicified volcanic tuff or rhyolitic jasper; chiefly microcrystalline quartz (SiO₂) with iron-oxide-rich orbicules

AI-generated identification · may be incorrect

Typically Mohs 6.5–7, opaque, with a waxy to vitreous polish; cream, brown, black, and orange-red circular orbs reflect iron oxides and altered volcanic material. Massive, microcrystalline structure with no visible cleavage; specific gravity about 2.6.

Identified August 30, 2026More sedimentary →

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At a glance

Common name: Polished orbicular jasper
Scientific name: Silicified volcanic tuff or rhyolitic jasper; chiefly microcrystalline quartz (SiO₂) with iron-oxide-rich orbicules
Category: sedimentary
Identified: August 30, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a small tumbled or polished piece; $30–$100+ for unusually colorful, well-patterned cabochons or rare locality material.

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 ash or tuff is altered and silicified, producing concentric mineral-filled spherulites; commonly Cenozoic to older volcanic-hosted material. The exact locality cannot be confirmed from the image.

Uses & applications

Used for cabochons, beads, carvings, polished specimens, and lapidary art; attractive orbicular patterns give it moderate collector appeal.

Geological facts

Orbicular jasper is often marketed under locality names such as Ocean Jasper, Madagascar jasper, or Leopard Skin Jasper, though trade names may overlap and are not always scientifically precise.

Field identification & locations

Identify by its hard, opaque body and rounded, concentric orb patterns that remain continuous through polish; jasper does not fizz in dilute acid and generally resists scratching by steel. Common sources include Madagascar, Mexico, Oregon, and Indonesia.