sedimentary

Tumbled yellow-brown stone, likely chert or jasper

Microcrystalline quartz (SiO₂), possibly iron-stained chert/jasper

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque mustard-brown color, waxy to dull luster, very fine-grained quartz with no visible cleavage. The rounded shape and smooth surface indicate mechanical tumbling or water wear.

Identified September 1, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert and jasper form when silica-rich fluids or biogenic silica replace sediments; iron oxides create yellow-brown coloration. Formation ages vary widely, from Precambrian to recent sedimentary settings.

Uses & applications

Used as an ornamental stone, cabochon material, bead, carving stock, and inexpensive lapidary specimen; not normally used structurally.

Geological facts

It should scratch ordinary glass but not be scratched by a steel knife. A conchoidal fracture and translucent thin edges support a quartz-rich identification.

Field identification & locations

Common in river gravels and sedimentary formations worldwide, especially areas with volcanic or silica-rich rocks. Exact identification would require a fresh fracture, streak, and hardness test; the photo cannot distinguish chert from jasper confidently.