mineral

Carnelian (Red Agate)

Chalcedony (SiO2 with Iron Oxide impurities)

Hardness: 6.5-7 (Mohs scale), Color: Brownish-red to orange, Luster: Vitreous to waxy, Crystal Structure: Hexagonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Hardness: 6

Identified April 18, 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 (Mohs scale), Color: Brownish-red to orange, Luster: Vitreous to waxy, Crystal Structure: Hexagonal (microcrystalline), Cleavage: None, Specific Gravity: 2.58-2.64

Formation & geological history

Formed in volcanic and sedimentary rocks as moisture-rich silica precipitates in cavities. Often found as rounded water-worn pebbles in riverbeds or beaches.

Uses & applications

Primarily used in jewelry (cabochons, beads), decorative carvings, and as a semi-precious gemstone in metaphysical practices.

Geological facts

Carnelian was used widely in ancient Rome to make signet rings for imprinting wax seals, as hot wax does not stick to it. It has been used for ornamentation for over 4,500 years, dating back to the Indus Valley Civilization.

Field identification & locations

Identify by its translucent brownish-red hue and waxy surface. Look in river gravels or coastal areas known for volcanic activity, such as parts of India, Brazil, or Oregon, USA.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

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