mineral

Carnelian

Carnelian (Cryptocrystalline Quartz, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Orange-red to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/hexagonal (microscopic); Cleavage: None; Specific gravity: 2.58-2.64

Hardness: 6
Color: Orange-red to brownish-red
Luster: Vitreous to waxy

Identified June 15, 2026More mineral →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Orange-red to brownish-red; Luster: Vitreous to waxy; Crystal structure: Trigonal/hexagonal (microscopic); Cleavage: None; Specific gravity: 2.58-2.64

Formation & geological history

Formed as secondary deposits of silica-rich fluids in volcanic cavities, sedimentary environments, or as water-worn pebbles in riverbeds. The orange color is caused by iron oxide (limonite or hematite) impurities.

Uses & applications

Primarily used in jewelry making (beads, cabochons), carvings, decorative ornaments, and as a popular specimen for crystal collectors.

Geological facts

Ancient Romans and Greeks used carnelian for signet rings and seals because hot wax does not stick to it. It has been used in jewelry for over 4,500 years, dating back to ancient Sumer and Egypt.

Field identification & locations

Identify in the field by its translucent body, waxy luster, and conchoidal fracture. Often found along beaches, riverbanks, and in areas of volcanic activity. Common locations include Brazil, India, Madagascar, and the USA (Pacific Northwest).