Goethite (Iridescent Stalactite) video

Goethite (Iridescent Stalactite)

Goethite – FeO(OH)
Elements: Iron, Oxygen, Hydrogen
Class: Oxides
Crystal System: Orthorhombic
Hardness: 5-5.5
Apatite
Talc (1)Diamond (10)
About as hard as a steel knife blade.
Origin: Tharsis, Huelva, Andalusia – Spain
Did you know?

Goethite, named for the poet Goethe, is a main ingredient of ordinary rust. It is also the stuff of limpet teeth, whose goethite fibers make one of the strongest natural materials known, tougher than spider silk.