mineral

Tumbled brown agate

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; translucent cream, honey-brown, and reddish-brown coloration; waxy to vitreous luster; cryptocrystalline quartz with no cleavage and conchoidal fracture. The smooth, glossy surface indicates tumbling or polishing.

Identified August 11, 2026More mineral →

Explore Tumbled brown 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

Forms when silica-rich groundwater fills cavities in volcanic rocks, depositing chalcedony and quartz in layers; iron oxides create the brown-red colors. Individual agate formation may span thousands to millions of years, commonly in Cenozoic or older volcanic terrain.

Uses & applications

Used for cabochons, beads, carvings, paperweights, and decorative objects; durable agate is also used for small industrial bearings and laboratory mortars.

Geological facts

Agate is a variety of banded or patterned chalcedony, though this specimen shows subtle rather than strong banding. Brown coloration commonly reflects hematite or goethite.

Field identification & locations

Identify by its hardness, translucency, waxy appearance, conchoidal fracture, and inability to scratch with a steel knife; it should scratch glass. Common sources include Brazil, Uruguay, India, Mexico, and the United States.