Cobaltite

A silvery cobalt arsenic sulfide with a pinkish tint, forming pyrite-like crystals.

Cobaltite specimen — Photo: User Tor Svensson, CC BY-SA 3.0, via Wikimedia Commons

How to identify cobaltite

Silver-white with a reddish tint.
Cubes and pyritohedrons like pyrite.
Pink 'cobalt bloom' crust on weathered pieces.

Often confused with

Pyrite
Pyrite is brass-yellow.
Compare side by side
Arsenopyrite
Arsenopyrite forms prisms and lacks the pink tint.
Compare side by side

Where it's found

Tunaberg, Sweden
Cobalt, Ontario
Morocco

Uses

Cobalt ore.

Rock tumbling

Not suitable for tumbling. Contains arsenic.

Did you know?

Cobalt is named after kobolds — goblins blamed by miners for toxic, worthless-seeming ores.

Think you could spot it from a blurry close-up?

Play today's Rocksday