Location: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
Sub euhedral striated prism with black color and sub metallic luster with some cleavage planes. Prism with 4.4 x 3.0 x 2.5cm and 98 grams. 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.