Dolomite

A calcium magnesium carbonate that forms whole mountain ranges of dolostone and pearly, curved 'saddle' crystals.

Dolomite specimen — Photo: Didier Descouens, CC BY-SA 4.0, via Wikimedia Commons

How to identify dolomite

Curved, saddle-shaped rhomb crystals.
Fizzes only weakly — or only when scratched into powder.
Pearly luster.
A bit harder than calcite.

Often confused with

Calcite
Calcite fizzes vigorously and is a bit softer.
Compare side by side

Where it's found

Eugui, Spain
The Dolomites, Italy
Missouri

Uses

Construction aggregate, magnesium source and soil conditioner.

Rock tumbling

Not suitable for tumbling.

Did you know?

It's named after French geologist Déodat de Dolomieu — and so are the Dolomite mountains.

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

Play today's Rocksday