mineral

Tumbled brown chalcedony (possibly carnelian or agate)

Microcrystalline quartz, SiO₂; exact variety cannot be confirmed from the photo

AI-generated identification · may be incorrect

Smooth, rounded, translucent-to-opaque brown and honey-yellow stone with a vitreous-to-waxy polish. Quartz has Mohs hardness 7, trigonal crystal structure, no cleavage, and specific gravity around 2.6; the image does not show diagnostic banding or other features to identify a precise variety.

Identified September 28, 2026More mineral →

Explore Tumbled brown chalcedony (possibly carnelian or agate) in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Silica-rich fluids deposit microcrystalline quartz in rock cavities and fractures; iron impurities can produce brown and yellow hues. Chalcedony forms in many geological settings and ages, commonly in volcanic rocks and sedimentary deposits.

Uses & applications

Used for beads, pendants, cabochons, and decorative objects; chalcedony is also collected as a lapidary material.

Geological facts

Tumbling smooths natural or cut rough stone in abrasive media. A definitive variety identification may require inspecting it in transmitted light or testing it in person.

Field identification & locations

Look for waxy luster, translucency at thin edges, and hardness sufficient to resist scratching by a steel knife; agate typically has visible bands, which are not apparent here. Chalcedony occurs worldwide, including Brazil, India, Madagascar, and the United States.