A stone guide

Chalcopyrite

Q: What is often mistaken for chalcopyrite?

Pyrite. Pyrite is paler brass and harder (6 to 6.5), a knife won't scratch it.

Nearly all vivid rainbow 'peacock ore' in shops is chalcopyrite given a quick acid bath to force the tarnish.

Sulfide (copper iron)MexicoSee treatment disclosure

Chalcopyrite is sulfide (copper iron), CuFeS₂. In the hand, it rates 3.5 to 4 on the Mohs scale, and it runs brass yellow and golden. Deeper brass-gold than pyrite and soft enough for a knife to scratch, often sold rainbow-tarnished as 'peacock ore'. The world's most important copper ore; notable: Mexico, Peru, China, Missouri (USA).

Family

Sulfide (copper iron)

Mohs

3.5 to 4

System

Tetragonal

Luster

Metallic

Gravity

4.1 to 4.3

Light

Opaque

What it is

The geology.

Chalcopyrite carries the formula CuFeS₂. It belongs to the tetragonal system. On paper it is sulfide (copper iron).

It sits at 3.5 to 4 on the Mohs scale. The surface reads metallic. Light behavior is opaque. Specific gravity runs 4.1 to 4.3. The streak is greenish black. It breaks with uneven fracture; brittle.

Deeper brass-gold than pyrite and soft enough for a knife to scratch, often sold rainbow-tarnished as 'peacock ore'.

Expect to see it as raw chunks, massive ore or acid-treated 'peacock ore'.

Where it comes from

The origins.

The world's most important copper ore; notable: Mexico, Peru, China, Missouri (USA).

On value, the database notes: common and affordable.

What people work with it for

Traditional associations.

In energy work traditions, associated with abundance and uplift.

Recorded here because it is part of how this material is sold, not because it is a property of the material.

What to look for

Spotting the real thing.

Deeper brass-gold than pyrite and soft enough for a knife to scratch, often sold rainbow-tarnished as 'peacock ore'.

Sold as 'bornite/peacock ore' after acid treatment, mislabeled, though the mineral itself is genuine.

Looks like	How to tell them apart
Pyrite	Pyrite is paler brass and harder (6 to 6.5), a knife won't scratch it
Gold	Gold is malleable and dents; chalcopyrite shatters
Bornite	True bornite shows bronze under its purple tarnish; chalcopyrite shows brass yellow

Check it yourself

At-home tests.

None of these need a lab. A 10x loupe, good daylight and a steady hand cover most of what a buyer needs to know about chalcopyrite.

Test	What you should see
Scratch check	Knife scratches it (Mohs 3.5 to 4)
By eye	Greenish-black streak
By eye	Heavy in hand (SG ~4.2)

Anything that scratches, burns or dissolves the piece is a lab job. Get it appraised rather than testing it apart.

How to live with it

Care & handling.

At 3.5 to 4 on the Mohs scale this is a soft material. Keep it as a display piece, store it apart from harder stones, and skip daily-wear settings.

It breaks with uneven fracture; brittle, which is worth knowing before you set it or drop it.

Warm water and a soft cloth clean almost everything. Ultrasonic tanks, steamers and household cleaners are where pieces get ruined.

Safe handling

Copper-iron sulfide, wash hands after handling crumbly pieces.

Pairs well with.

For the serious reader

A deeper look.

Extended detail on composition, sourcing, authentication and market value.

The physical record

The formula on record is CuFeS₂. Crystal system: Tetragonal. Specific gravity: 4.1 to 4.3. Streak: Greenish black. Cleavage and fracture: Uneven fracture; brittle.

How it reaches the market

The world's most important copper ore; notable: Mexico, Peru, China, Missouri (USA).

What it gets confused with

Pyrite: Pyrite is paler brass and harder (6 to 6.5), a knife won't scratch it. Gold: Gold is malleable and dents; chalcopyrite shatters. Bornite: True bornite shows bronze under its purple tarnish; chalcopyrite shows brass yellow.

What it is worth

Common and affordable.

Where buyers get caught

Sold as 'bornite/peacock ore' after acid treatment, mislabeled, though the mineral itself is genuine.

One more thing

Nearly all vivid rainbow 'peacock ore' in shops is chalcopyrite given a quick acid bath to force the tarnish.

From the Beyond Bohemian library

An education-first guide.

No product links here. We do not sell chalcopyrite, and a guide that only covers our own shelves would not be much of a guide.

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Chalcopyrite

The geology.

The origins.

Traditional associations.

Spotting the real thing.

At-home tests.

Care & handling.

Pairs well with.

A deeper look.

The physical record

How it reaches the market

What it gets confused with

What it is worth

Where buyers get caught

One more thing

An education-first guide.

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Chalcopyrite

The geology.

The origins.

Traditional associations.

Spotting the real thing.

At-home tests.

Care & handling.

Pairs well with.

A deeper look.

The physical record

How it reaches the market

What it gets confused with

What it is worth

Where buyers get caught

One more thing

An education-first guide.

Most items are one of one or come in limited batches. See them, and the stories behind them, before anyone else.