Wolframite (Ferberite).
 
 
From: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
 
 
Tabular prism with vertical striation, with 3.2 x 1.8 x 1.5cm and 38 grams, black, opaque and with semi-metallic lustre. 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.