Really a definitive specimen for this classic mineral association from Panasqueira Mines, Covilhã, Castelo Branco, Portugal – Ferberite, Arsenopyrite, Siderite and minor Mica (on the back) are simultaneously present with perfect composition, shape and brilliancy ; the specimen is partially covered by a Siderite crystals frosting – overall size 9.5x8x4.7 cm. – main  Ferberite 2.7 cm.