mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2)

Hardness: 6.5–7 on Mohs scale; Color: Reddish-brown to orange-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58–2.64.

Hardness: 6
Color: Reddish-brown to orange-red
Luster: Vitreous to waxy

Identified April 1, 2026More mineral →

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Physical properties

Hardness: 6.5–7 on Mohs scale; Color: Reddish-brown to orange-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None; Specific gravity: 2.58–2.64.

Formation & geological history

Formed through the deposition of silica from groundwater into cavities (vugs) of volcanic rocks. The red coloring is caused by iron oxide (hematite) impurities.

Uses & applications

Used primarily in jewelry making, cabochons, beads, seal rings, and as a decorative stone for collectors.

Geological facts

Carnelian has been used as a gemstone since the Early Neolithic period. It was highly prized in Ancient Egypt, where it was believed to assist the soul in its journey to the afterlife.

Field identification & locations

Identify by its waxy luster, translucency when held to light, and lack of visible crystal grains. Often found as water-worn pebbles in riverbeds or within basaltic host rocks.