sedimentary

Dark reddish-brown stone, likely iron-rich chert or weathered jasper

Microcrystalline quartz (SiO₂), possibly hematite/goethite-bearing

AI-generated identification · may be incorrect

Opaque, dark red-brown, dull to subtly waxy luster, irregular rounded form, and no visible cleavage; quartz-rich material is typically Mohs 6.5–7, with specific gravity around 2.6–2.7.

Identified August 29, 2026More sedimentary →

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Physical properties

Opaque, dark red-brown, dull to subtly waxy luster, irregular rounded form, and no visible cleavage; quartz-rich material is typically Mohs 6.5–7, with specific gravity around 2.6–2.7.

Formation & geological history

Likely formed by silica replacement or precipitation in sedimentary settings, with iron oxides producing the red-brown color; age depends on its source formation and cannot be determined from the image.

Uses & applications

Commonly used as lapidary rough, cabochons, beads, and ornamental stone; ordinary pieces have little industrial or jewelry value.

Geological facts

The appearance is consistent with jasper or ferruginous chert, but exact identification requires a hardness test, streak, or close examination of texture.

Field identification & locations

Look for a fine-grained texture, conchoidal fracture, and inability to scratch it with a steel knife; reddish-brown streak suggests iron oxides. Such material occurs worldwide, including the western United States, Australia, India, and Brazil.