gemstone

Tumbled carnelian agate (likely quartz-rich chalcedony)

Microcrystalline quartz, SiO₂; chalcedony with iron-oxide coloration

AI-generated identification · may be incorrect

Orange-red translucent zones with a gray-white, waxy interior and polished surface; hardness about 6.5–7 Mohs, trigonal quartz structure, no visible cleavage, specific gravity roughly 2.6. The bright white area may be quartz, druzy, or a natural inclusion; strong flash limits detail.

Identified September 17, 2026More gemstone →

Explore Tumbled carnelian agate (likely quartz-rich chalcedony) 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, with iron oxides producing orange-red colors; commonly associated with volcanic rocks, typically formed from Paleozoic to Cenozoic volcanic activity depending on locality.

Uses & applications

Used for beads, cabochons, carvings, ornamental objects, and inexpensive collector specimens; attractive banding or translucency increases jewelry value.

Geological facts

Carnelian is the orange-red variety of chalcedony, while agate usually shows banding or multiple colored zones. Heat treatment can intensify red-orange coloration.

Field identification & locations

Identify by its glassy-to-waxy luster, very high hardness, curved conchoidal fracture, translucency, and resistance to scratching by a steel knife. Common sources include Brazil, Uruguay, India, Madagascar, and the United States.