From: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
Aggregate of striated prismatic crystals with bladded habit, 5.0 x 5.0 x 2.5cm and 141 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.