Dumortierite

A denim-blue aluminum borosilicate, usually as fibrous masses or embedded in quartz.

Dumortierite specimen — Photo: Géry PARENT, CC BY-SA 3.0, via Wikimedia Commons

How to identify dumortierite

Denim blue to violet, opaque and fibrous.
Very hard and tough.
Often speckled through quartz.

Often confused with

Sodalite
Sodalite is softer and veined with white.
Compare side by side
Lapis Lazuli
Lapis has gold pyrite flecks.
Compare side by side

Where it's found

Madagascar
Brazil
Nevada
Arizona

Uses

Ceramic porcelain and decorative stone.

Rock tumbling

Great for tumbling.

Did you know?

Much 'blue aventurine' on the market is quartz filled with dumortierite.

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