mineral

Tumbled jasper/chert, possibly brecciated jasper

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

AI-generated identification · may be incorrect

Opaque cream, tan, and rusty-brown patches with a smooth tumbled surface and dull to waxy luster; hardness about 6.5–7 Mohs, no visible cleavage, and conchoidal fracture typical of quartz-rich material. Its rounded shape indicates human tumbling or natural abrasion.

Identified September 12, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or replaces sediment, with iron oxides producing the brown coloration; individual pieces may range from Paleozoic to Cenozoic depending on source locality. The exact origin cannot be determined from the photograph alone.

Uses & applications

Used as a lapidary stone for cabochons, carvings, polished stones, and inexpensive jewelry; attractive pieces are collected as decorative specimens.

Geological facts

Jasper is an opaque variety of chalcedony or microcrystalline quartz, while brecciated varieties contain angular fragments cemented by silica. Color zoning commonly reflects changing iron content during formation.

Field identification & locations

Identify by its glassy/waxy appearance, high hardness, opaque patterned interior, and inability to scratch with a steel knife; it should scratch ordinary glass. Common sources include Oregon, Idaho, California, Brazil, Madagascar, and India.