mineral

Carnelian (a variety of Chalcedony)

SiO2 (Silicon Dioxide) with Iron Oxide impurities

AI-generated identification · may be incorrect

Hardness: 6.5–7 (Mohs scale); Color: Orangey-red, brownish-red, or translucent orange; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58–2.64.

Hardness: 6
Color: Orangey-red, brownish-red, or translucent orange
Luster: Vitreous to waxy

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in volcanic environments where silica-rich fluids permeate cavities (vugs) in igneous rocks. As the fluids cool, they deposit microcrystalline quartz. The reddish color comes from iron oxide (hematite) inclusions occurring during or after formation.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and lapidary art. Historically used for signet rings and wax seals because hot wax does not stick to it.

Geological facts

In ancient Egypt, Carnelian was known as 'the setting sun' and was used in the burial of the dead to assist transition to the afterlife. It is the modern birthstone for the month of July in some cultures.

Field identification & locations

Identify by its waxy luster and translucent deep orange-to-red coloring without the distinct parallel banding seen in regular agate. Common locations include Brazil, India, Madagascar, and Uruguay. To identify in the field, look for a smooth, glass-like fracture (conchoidal) and resistance to scratching from a steel knife.