Iron-stained chert (possible jasper)

Opaque tan to brown, rough and nodular, with a dull-to-waxy luster and irregular fracture; likely Mohs hardness 6.5–7. The image does not show diagnostic crystal faces or cleavage.

Chert forms when silica-rich material precipitates or replaces sediment; iron oxides can tint it brown. Its precise age and formation setting cannot be determined from the photograph.

Chert is used historically for tools and occasionally as a decorative stone; attractive jasper varieties are cut and polished for jewelry and collecting.

Jasper is an opaque, colored variety of microcrystalline quartz, but color alone cannot establish that this specimen is jasper.

The tan, waxy-looking material and irregular surfaces are consistent with chert, though the cavities and lumpy shape make identification uncertain. A scratch test on an inconspicuous spot—quartz should scratch glass—can help; the reported location is too coarse to meaningfully narrow the identification.