mineral

Carnelian (a variety of Chalcedony)

Silicon dioxide (SiO2) with iron oxide impurities

Hardness: 6.5–7 (Mohs scale); Color: Orange to reddish-brown; Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None (conchoidal fracture); Specific gravity: 2.58–2.64

Hardness: 6
Color: Orange to reddish-brown
Luster: Vitreous to waxy

Identified March 25, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed through the deposition of silica from groundwater into cavities of igneous rocks, particularly volcanic lavas. The reddish hue is caused by iron oxide (hematite) inclusions. It can be found in formations ranging from ancient Precambrian to relatively recent volcanic deposits.

Uses & applications

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

Geological facts

Ancient Egyptians called carnelian 'the setting sun' and believed it had protective powers. It was one of the first gemstones used in bead making and was frequently used by Romans for wax seal impressions because hot wax does not stick to it.

Field identification & locations

Identify by its translucent orange-red glow when held to a light source and its smooth, waxy texture. It is commonly found in riverbeds or beaches where volcanic rocks have weathered down. Major sources include Brazil, India, Uruguay, and Madagascar.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral