mineral

Carnelian

Carnelian (Cryptocrystalline Quartz, SiO2)

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

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

Identified July 6, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in silica-rich groundwater that precipitates in the cavities of volcanic and sedimentary rocks. Its characteristic color comes from iron oxide (hematite) impurities. It can date from various geological periods depending on the host rock.

Uses & applications

Widely used for gemstone carvings, beads, cabochons for jewelry, and as a decorative collector's stone.

Geological facts

Carnelian was highly prized in ancient times; the Romans used it for signet rings because hot wax does not stick to it. It has been used as a decorative gemstone for over 4,500 years.

Field identification & locations

Identify in the field by its translucent orange-red color and waxy luster. It often occurs as nodules or as part of larger agate deposits in riverbeds or coastal areas like those in India or Brazil.