mineral

Polished jasper or iron-stained chert

Microcrystalline quartz (SiO₂), commonly chalcedony with iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; orange-brown, cream, and gray coloration; waxy to subvitreous luster; cryptocrystalline structure with no visible cleavage and conchoidal fracture. The rounded shape appears tumbled or naturally water-worn.

Identified August 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater replaces or fills cavities in volcanic or sedimentary rocks, with hematite/goethite producing the orange-brown colors. Formation age varies widely by locality, commonly Paleozoic to Cenozoic.

Uses & applications

Used for cabochons, carvings, beads, ornaments, and lapidary specimens; attractive pieces have modest collectible value.

Geological facts

Jasper is an opaque variety of chalcedony, while chert is a closely related microcrystalline quartz rock. Iron staining can create vivid brecciated, orbicular, or landscape-like patterns.

Field identification & locations

Identify by its glass-scratching hardness, opaque appearance, waxy luster, and lack of cleavage; acid produces no fizz. Common in volcanic terrains, river gravels, and silica-rich sedimentary formations worldwide.