mineral

Carnelian

Carnelian (SiO2 - Silicon Dioxide)

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

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

Identified March 13, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

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

Formation & geological history

Formed as a cryptocrystalline variety of quartz within volcanic and sedimentary rocks. Its reddish-orange color is derived from iron oxide impurities (hematite). It can be found in formations ranging from recent river sediments to ancient volcanic beds millions of years old.

Uses & applications

Primarily used in jewelry, as gemstones, beads, and for cabochons. Historically used for intaglio seals and talismans. Also used as decorative ornamental stones and by collectors.

Geological facts

Ancient Romans used carnelian for signet rings because hot wax does not stick to it. It has been used as a gemstone for over 4,500 years, appearing in Sumerian and Egyptian burials.

Field identification & locations

Identify in the field by its translucent properties and uniform reddish-orange hue with a waxy luster. Common locations include Brazil, India, Madagascar, and Uruguay. Look for rounded nodules in riverbeds or within cavities in volcanic rocks.