mineral

Peacock Ore (Bornite or Iridescent Chalcopyrite)

Bornite (Cu5FeS4) or Chalcopyrite (CuFeS2) with tarnish

Hardness: 3-3.25; Color: Copper-red to bronze on fresh surfaces, iridescent metallic blues, purples, and yellows when tarnished; Luster: Metallic; Crystal Structure: Orthorhombic/Tetragonal; Specific Gravity: 5.06-5.08

Hardness: 3-3
Luster: Metallic

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed in hydrothermal veins, contact metamorphic zones, and magmatic segregations. It occurs in massive forms alongside other copper minerals like chalcocite and malachite.

Uses & applications

Major ore of copper. It is also highly sought after by mineral collectors for its vibrant iridescent metallic tarnish and used as decorative 'pocket stones' or in metaphysical collections.

Geological facts

Commonly known as 'Peacock Ore' because the vivid rainbow of colors resembles peacock feathers. While it occurs naturally, many commercial specimens are chalcopyrite treated with acid to enhance the iridescence.

Field identification & locations

Identified in the field by its metallic luster and distinctive purple-blue tarnish. Natural bornite streaks grayish-black. Found in major copper mining regions like Montana (USA), Cornwall (UK), and Chile.

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