Location: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
Two black Ferberite prisms (ferriferous Wolframite) 2cm long within a matrix of small lamellar crystals of yellow Siderite. Sample with 2.5 x 1.7 x 1.5cm. Formed in mineralized veins of quartz, sulfides, wolframite, cassiterite, micas, fluorite, carbonates, among others, associated with the generation of a greisen dome by granitic intrusion in Paleozoic schists and graywackes.