mineral

Tumbled carnelian agate

Microcrystalline quartz (chalcedony), SiO₂; iron-oxide colored

AI-generated identification · may be incorrect

Typically reddish-brown, orange, and translucent to opaque with a waxy-to-glassy luster and no visible cleavage; Mohs hardness 6.5–7, trigonal quartz structure, specific gravity about 2.6. The rounded, glossy shape indicates mechanical tumbling and polishing.

Identified September 17, 2026More mineral →

Explore Tumbled carnelian 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 and fractures in volcanic rocks, with iron oxides producing red and brown colors; commonly Paleozoic–Cenozoic, though ages vary by deposit. This specimen is a polished human-processed geological material.

Uses & applications

Used for inexpensive jewelry, beads, carvings, cabochons, ornaments, and lapidary practice; it has little construction use as a small specimen.

Geological facts

Carnelian is the orange-red variety of chalcedony, while banded material is commonly called agate. Heating can intensify or alter its red-orange coloration.

Field identification & locations

Identify by hardness, waxy luster, red-orange coloration, translucency at thin edges, and lack of cleavage; common sources include Brazil, India, Uruguay, Madagascar, and the United States. It should not scratch easily with a steel knife, though testing can damage polish.