Arsenopyrite

An iron arsenic sulfide and the main ore of arsenic. It smells of garlic when struck.

Arsenopyrite specimen — Photo: Robert M. Lavinsky, CC BY-SA 3.0, via Wikimedia Commons

How to identify arsenopyrite

Silvery-white metallic, diamond-shaped prisms.
Garlic smell when hammered.
Harder than a knife.

Often confused with

Marcasite
Marcasite is paler brass-yellow.
Compare side by side
Pyrite
Pyrite is brassy yellow and forms cubes.
Compare side by side

Where it's found

Panasqueira, Portugal
Hunan, China
Bolivia

Uses

Arsenic ore; often contains gold.

Rock tumbling

Not suitable for tumbling. Contains arsenic; wash your hands after handling.

Did you know?

The garlic smell when it's hit comes from arsenic vapor — don't sniff it.

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