Chalcopyrite Crystals from Peru

Chalcopyrite is a brassy yellow coloured mineral with a metallic lustre.  It has been widely used as an ore of copper for about five thousands years.  It currently accounts for half of the world's copper production. 

Chalcopyrite is a copper iron sulphide mineral meaning it's a chemical compound of copper, iron and sulphur.

Although other minerals contain a higher percentage of copper, chalcopyrite is the most important ore because of its abundance.

Chalcopyrite is often confused for the mineral pyrite.  On Mohs scale of mineral hardness pyrite grades 6 to 6.5, chalcopyrite grades 3.5 to 4 so is much softer. Like pyrite it's also brittle so must be handled carefully.

From appearance alone chalcopyrite can also be confused for gold but at 2.5 on Mohs scale, gold is even softer.

Chalcopyrite conducts electricity and is prone to tarnishing.  Tarnished material can exhibit a dull grey-green colour.

After being exposed to acid shades of red, blue and purple can often be seen. These colours are often iridescent.

Chalcopyrite that's been soaked in acid is often sold as Peacock Ore.

Peacock Ore is a trade name for bornite which is also a copper iron sulphide mineral and an ore of copper.  As bornite tarnishes through exposure to air it naturally forms an iridescent tarnish.  This produces vivid shades of blue, purple, red, green and yellow.

Bornite is not particularly common so is highly sought after by collectors.

Where the iridescent colours look excessively vibrant the material is likely to be chalcopyrite that's been treated with acid.

Our chalcopyrite crystals are size medium.  Size can vary from piece to piece.  

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