mineral

Carnelian

Carnelian (Silica/Chalcedony, SiO2)

Hardness: 6.5-7 on Mohs scale; Color: Orange, reddish-brown, semi-transparent to translucent; Luster: Waxy to vitreous; Crystal Structure: Trigonal (microcrystalline); Cleavage: None; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Orange, reddish-brown, semi-transparent to translucent
Luster: Waxy to vitreous

Identified June 30, 2026More mineral →

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Physical properties

Formation & geological history

Forms through the deposition of silica from groundwater in volcanic rock cavities or sedimentary environments. The orange hue is caused by iron oxide (hematite) impurities. It can be found in deposits of all geological ages.

Uses & applications

Primarily used as a gemstone for jewelry (cabochons, beads), decorative carvings, and seal stones. Historically used for signet rings and amulets.

Geological facts

Carnelian was highly prized in ancient Egypt, where it was thought to provide protection for the soul in the afterlife. It was also used by Roman engravers for signet rings because hot wax does not stick to it.

Field identification & locations

Identify by its characteristic waxy luster and translucent orange-red color. It is often found as water-worn pebbles in riverbeds or within basaltic host rocks. Common locations include Brazil, India, Uruguay, and Madagascar.