sedimentary

Tumbled brown chert or jasper

Microcrystalline quartz (SiO₂), likely chert/jasper

AI-generated identification · may be incorrect

Opaque tan-brown, dull to waxy luster, very fine-grained and massive with no visible crystals or cleavage; hardness about 6.5–7 Mohs, specific gravity roughly 2.6. The rounded edges suggest natural weathering or tumbling.

Identified September 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert forms when microcrystalline silica replaces or accumulates in sedimentary rocks, often from silica-rich marine organisms; jasper is an iron- and impurity-rich opaque variety. Exact age and locality cannot be determined from the image.

Uses & applications

Used for ornamental carvings, cabochons, beads, lapidary objects, and historically as a toolstone; not generally used as a major construction stone in this small form.

Geological facts

A steel file should scratch it only with difficulty, while it can scratch ordinary glass. Brown coloration commonly comes from iron oxides or hydroxides.

Field identification & locations

Common in sedimentary terrains, gravel deposits, and riverbeds worldwide. A porcelain-like fracture, lack of visible grains, and resistance to scratching support chert/jasper identification; a close visual distinction is not certain from the photo alone.