mineral

Chalcopyrite

Chalcopyrite (CuFeS2)

Hardness: 3.5-4 (Mohs), Color: Brass yellow often with iridescent tarnish, Luster: Metallic, Crystal Structure: Tetragonal, Cleavage: Indistinct, Specific Gravity: 4.1 to 4.3

Hardness: 3

Identified June 15, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 3.5-4 (Mohs), Color: Brass yellow often with iridescent tarnish, Luster: Metallic, Crystal Structure: Tetragonal, Cleavage: Indistinct, Specific Gravity: 4.1 to 4.3

Formation & geological history

Formed in hydrothermal veins, contact metamorphic deposits, and as a primary mineral in igneous rocks. It is created through the precipitation of copper-rich fluids in sulfur-rich environments.

Uses & applications

The most important ore of copper worldwide. While usually too brittle for jewelry, iridescent specimens (often sold as 'Peacock Ore') are popular for collectors.

Geological facts

Chalcopyrite is often confused with Gold, but it is much more brittle and will break when struck rather than flattening. It is often found associated with other sulfides like pyrite and sphalerite.

Field identification & locations

Identify in the field by its brassy color, greenish-black streak, and tendency to tarnish into purple or blue hues. It is found in mining districts globally, such as Arizona, Chile, and Cornwall.