How to identify Peacock Ore

To correctly identify Peacock Ore (Bornite), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Freshly broken surfaces are reddish-brown to copper-red, rapidly tarnishing to iridescent shades of blue, purple, red, and green.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Metallic.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically massive, granular, or disseminated. Less commonly found as distinct crystals.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Crystals are rare, usually pseudocubic dodecahedra or octahedra, but most commonly found as massive aggregates or disseminated grains.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Poor or indistinct cleavage on {111}.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Hydrothermal veins, porphyry copper deposits, skarn deposits, massive sulfide deposits, and supergene enrichment zones.

Key Facts

Hardness

3.0 on the Mohs scale.

Specific Gravity

4.9-5.3 g/cm³.

Crystal System

Tetragonal (pseudocubic) at room temperature, but cubic above 228°C.

Color

Reddish-brown to copper-red, tarnishing to iridescent blue, purple, red, green.

Luster

Metallic.

Transparency

Opaque.

Fracture

Conchoidal to uneven.

Cleavage

Poor or indistinct on {111}.

Composition

Copper iron sulfide (Cu5FeS4).

Physical characteristics

• Crystal Habit: Massive, granular, disseminated; rarely as pseudocubic dodecahedral or octahedral crystals.
• Cleavage Type: Poor/indistinct on {111}.
• Fracture Type: Conchoidal to uneven.
• Tenacity: Brittle.
• Luster Type: Metallic.

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