mineral

Likely tumbled brown chalcedony or jasper

Microcrystalline quartz, SiO₂; possibly iron-rich jasper

AI-generated identification · may be incorrect

Small, smooth, opaque-to-translucent dark brown pebble with a glassy-to-waxy luster and no visible cleavage. Quartz hardness is about 7 Mohs; specific gravity is approximately 2.6.

Identified August 23, 2026More mineral →

Explore Likely tumbled brown chalcedony or jasper in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Small, smooth, opaque-to-translucent dark brown pebble with a glassy-to-waxy luster and no visible cleavage. Quartz hardness is about 7 Mohs; specific gravity is approximately 2.6.

Formation & geological history

Chalcedony and jasper form when silica-rich groundwater fills cavities or fractures, with iron oxides producing brown coloration. The image cannot establish a precise geological age or locality.

Uses & applications

Commonly sold as inexpensive tumbled stones, cabochons, beads, and ornamental material; jasper is also used for carvings and decorative objects.

Geological facts

The specimen may also be brown agate, smoky quartz, or polished iron-rich chert; these varieties can look similar in a low-resolution photograph.

Field identification & locations

Check whether it scratches glass but not a steel file, and inspect with a flashlight for translucency or banding; an acid test is unnecessary. Similar material occurs worldwide, especially in volcanic and sedimentary silica deposits.