gemstone

Tumbled carnelian (likely agate/chalcedony)

Cryptocrystalline quartz, SiO₂; iron-oxide-colored chalcedony

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, translucent orange-red to brown, with waxy to vitreous luster and no visible cleavage. The rounded, polished form and cloudy banding are consistent with chalcedony, though the image alone cannot confirm the exact variety.

Identified August 16, 2026More gemstone →

Explore Tumbled carnelian (likely agate/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 in volcanic rock, later incorporating iron oxides that produce orange-red color; commonly Cenozoic to older, depending on the host deposit.

Uses & applications

Used for beads, cabochons, carvings, and inexpensive ornamental jewelry; polished tumbled pieces are popular collectors’ specimens.

Geological facts

Carnelian is an orange-red variety of chalcedony, while paler or strongly banded material may be classified as agate. Heating can intensify its red color.

Field identification & locations

Identify by its glassy/waxy translucence, smooth conchoidal fracture, absence of cleavage, and hardness that resists scratching by steel. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.