Goethite from Filón Sur open pit, Spain

Goethite from the Filón Sur open pit (Filón Sur Mine), Tharsis Mines, Tharsis, Alosno, Huelva, Andalusia, Spain

Specimens of Goethite from the Filón Sur open pit mine near Tharsis.

These pieces often have an iridescent rainbow sheen, a little like oil on water. Best seen under bright light. It is worth pointing out that not all the pieces are like #1 though - the iridescence may only cover a small area of the piece and may not be as bright as that first specimen.