Rocksday

Goethite

An iron oxyhydroxide forming dark bubbly or velvety masses, and the main component of rust.

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

How to identify goethite

  • Black-brown botryoidal masses, often with iridescent tarnish.
  • Yellow-brown streak.
  • Radiating fibers when broken.

Often confused with

Where it's found

  • Pikes Peak, Colorado
  • Cornwall, England
  • Germany

Uses

Iron ore and brown ochre pigment.

Rock tumbling

Can be tumbled with care.

Did you know?

It's named after the German writer Johann Wolfgang von Goethe, who collected minerals.

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