metamorphic

Polished leopard-skin jasper

Silicified volcanic rock, chiefly microcrystalline quartz (SiO₂) with iron oxides and dark amphibole/pyroxene minerals

AI-generated identification · may be incorrect

Typically Mohs 6.5–7; mustard-yellow, cream, black, and brown mottling; opaque, waxy to vitreous luster; cryptocrystalline quartz with no visible cleavage. The rounded, glossy surface indicates a tumbled or polished specimen.

Identified September 15, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when silica-rich fluids replace and cement volcanic or brecciated rock, with iron and manganese producing the spotted colors; commonly Paleozoic to Mesozoic, depending on locality. Common sources include Mexico, Oregon, and other volcanic regions.

Uses & applications

Used for cabochons, beads, carvings, polished stones, and decorative objects; valued mainly as an ornamental lapidary material.

Geological facts

“Leopard jasper” is a trade name rather than a single formally defined mineral species; similar material may be sold as leopard-skin rhyolite or orbicular jasper.

Field identification & locations

Identify by its opaque spotted pattern, fine-grained silica texture, and lack of obvious crystals or cleavage; a streak test is usually white to pale. Exact identification requires locality or thin-section analysis.