gemstone

Tumbled carnelian/chalcedony

Carnelian, orange-red microcrystalline quartz (SiO₂), a variety of chalcedony

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, translucent orange to red-brown, with waxy to vitreous luster and no visible cleavage. The specimen appears naturally or artificially tumbled, with iron-oxide coloration and a small dark mineral inclusion or cavity.

Identified August 29, 2026More gemstone →

Explore Tumbled carnelian/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 volcanic cavities or fractures, with iron impurities producing red-orange colors; deposits range from ancient volcanic settings to younger sedimentary gravels. Geological age varies by locality.

Uses & applications

Used for beads, cabochons, carvings, ornaments, and inexpensive jewelry; polished pieces are popular lapidary and metaphysical specimens.

Geological facts

Carnelian is commonly heat-treated to intensify its red-orange color, sometimes from paler chalcedony or agate. It belongs to the quartz family despite lacking large visible crystals.

Field identification & locations

Identify by its even orange-red color, translucency, waxy surface, and quartz-like hardness; it should scratch glass but not be scratched by a steel blade. Common sources include India, Brazil, Uruguay, Madagascar, and Botswana.