mineral

Copper Ore (likely Chalcopyrite in Matrix)

Chalcopyrite (CuFeS2)

Mohs hardness: 3.5 - 4. Color: Brassy yellow to iridscent purplish-green when tarnished. Luster: Metallic. Crystal structure: Tetragonal. Specific gravity: 4.1 - 4.3.

Hardness: 3
Color: Brassy yellow to iridscent purplish-green when tarnished
Luster: Metallic

Identified June 5, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Mohs hardness: 3.5 - 4. Color: Brassy yellow to iridscent purplish-green when tarnished. Luster: Metallic. Crystal structure: Tetragonal. Specific gravity: 4.1 - 4.3.

Formation & geological history

Forms primarily in hydrothermal veins from hot, mineral-rich fluids and in porphyry copper deposits. It can also be found in contact metamorphic rocks and as a primary mineral in igneous rocks via magmatic segregation.

Uses & applications

The primary ore of copper; used for manufacturing electrical wiring, plumbing, electronics, and industrial alloys like brass and bronze. Collectors value unusually large or colorful crystals.

Geological facts

Chalcopyrite is often called 'Peacock Ore' when it displays vibrant iridescent tarnishing (though Bornite is also sold under this name). It is the most abundant copper-bearing mineral in the Earth's crust.

Field identification & locations

Look for metallic, brassy-yellow patches that are much softer than gold. It is commonly found in mining districts in Chile, Peru, Arizona (USA), and Canada. It will leave a greenish-black streak when rubbed on a porcelain plate.

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

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic