mineral

Polished jasper slab

Jasper, an opaque microcrystalline variety of chalcedony (SiO₂), colored mainly by iron oxides

AI-generated identification · may be incorrect

Typically Mohs 6.5–7; mustard yellow, brown, black, and gray with opaque earthy patterns, waxy-to-vitreous luster, and no visible cleavage. The specimen appears sawn and polished, with a natural rough rind and fractures.

Identified September 15, 2026More mineral →

Explore Polished jasper slab in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms when silica-rich groundwater replaces or fills cavities and fractures in volcanic or sedimentary host rock; iron and manganese oxides create the colors. Jasper deposits range from Precambrian to recent, depending on locality.

Uses & applications

Used for cabochons, beads, carvings, decorative slabs, and lapidary collections; durable enough for small ornamental objects but not usually major construction stone.

Geological facts

Jasper is technically a rock dominated by microcrystalline quartz rather than a single pure mineral. Its intricate patterns are produced by brecciation, replacement, fluid flow, and staining.

Field identification & locations

Identify it by its opacity, fine grain, conchoidal fracture, hardness, and resistance to scratching by steel; it should not fizz in dilute acid. Common sources include India, Madagascar, Brazil, the United States, and Australia.