From: Panasqueira Mine, Covilhão, Castelo Branco, Portugal.
  
Aggregate of striated prismatic  crystals with 3,5 x 3,1 x 2,6cm and 74 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.