mineral

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Hardness: 6.5-7 Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.58–2.64.

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

Identified March 17, 2026More mineral →

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Physical properties

Hardness: 6.5-7 Mohs scale; Color: Reddish-orange to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None; Specific gravity: 2.58–2.64.

Formation & geological history

Formed from the deposition of silica in gas cavities of volcanic rock. The color comes from iron oxide (hematite) impurities. It can be found in sedimentary environments through the weathering of igneous rocks.

Uses & applications

Predominantly used as a gemstone for jewelry (cabochons, beads), decorative carvings, and seal stones. Historically used for signet rings due to its non-stick property with hot wax.

Geological facts

Carnelian has been used for over 4,000 years, appearing in ancient Egyptian burials as a symbol of life. Napoleon Bonaparte famously wore a carnelian seal found during his Egyptian campaign.

Field identification & locations

Identify by its translucent reddish-orange hue and waxy surface. In the field, look for smooth, water-worn pebbles in riverbeds or within basalt host rocks. Common locations include Brazil, India, Uruguay, and Madagascar.