FeWO₄

These samples of ferberite are displayed in the Smithsonian Museum of Natural History. Ferberite is a oxide mineral of tungsten with the composition FeWO₄. The sample at left is about 25 cm across and is from Nugget claim, Rollinsville, Colorado.

This is ferberite with arsenopyrite and siderite. The black, shiny crystals are ferberite, an ore of tungsten. The silvery crystals are arsenopyrite, an ore of arsenic. Siderite crystals form the frosting. This sample is about 15 cm across and is from Panasqueira, Portugal.

This is another ferberite sample from Panasqueira, Portugal. It is about 25 cm across.