mineral

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), possibly iron-bearing jasper

AI-generated identification · may be incorrect

Opaque to slightly translucent tan-brown stone with waxy luster and subtle fibrous/patchy internal texture; quartz hardness is about 7 Mohs, with no visible cleavage and conchoidal fracture. The rounded shape indicates tumbling or natural abrasion.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Likely formed when silica-rich groundwater replaced or cemented sediment, producing microcrystalline quartz; iron impurities create the brown coloration. Exact geological age and locality cannot be determined from the image.

Uses & applications

Used as a lapidary, cabochon, bead, and decorative stone; common material has modest collectible value.

Geological facts

Jasper is an opaque variety of chalcedony or microcrystalline quartz, while chert is a closely related silica-rich rock. A scratch test with steel or glass can help distinguish it from softer brown stones.

Field identification & locations

Common sources include sedimentary formations worldwide, especially the United States, Mexico, Madagascar, Brazil, and Australia. Confirm identification by testing hardness, examining a fresh edge for waxy/conchoidal fracture, and checking for uniform fine-grained texture.