sedimentary

Orbicular jasper (often sold as leopard-skin jasper)

Silicified volcanic tuff/rhyolite; chiefly microcrystalline quartz and chalcedony (SiO₂), with iron oxides and altered volcanic minerals

AI-generated identification · may be incorrect

Typically opaque, dark gray-brown with cream, tan, and yellow orbicular patterns; waxy to vitreous luster when polished. Mohs hardness about 6.5–7; cryptocrystalline, massive, with no obvious cleavage; specific gravity roughly 2.5–2.7.

Identified September 15, 2026More sedimentary →

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At a glance

Common name: Orbicular jasper (often sold as leopard-skin jasper)
Scientific name: Silicified volcanic tuff/rhyolite; chiefly microcrystalline quartz and chalcedony (SiO₂), with iron oxides and altered volcanic minerals
Category: sedimentary
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $10–$40 for a polished palm stone; $50–$150+ for larger, exceptionally patterned lapidary pieces.

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 silicify volcanic ash or lava, preserving spherulitic or orb-like textures; generally Cenozoic volcanic material, though age depends on locality. Similar material is commonly associated with altered rhyolitic terrains.

Uses & applications

Used for cabochons, beads, carvings, palm stones, and decorative objects; occasionally marketed as a lapidary jasper. It has little industrial value beyond ornamental stone.

Geological facts

The concentric spots are geological orbicules or altered spherulites, not animal markings. “Leopard-skin jasper” is a commercial name and may refer to several visually similar materials.

Field identification & locations

Identify it by its opaque silica-rich body, hardness, conchoidal fracture, and natural orbicular pattern; it will not fizz in dilute acid. Commonly reported from Mexico, Madagascar, Indonesia, and the western United States.