Location: Mina da Panasqueira, Covilhã, Castelo Branco, Portugal.
Two hexagonal and transparent prisms with 5.0 x 2.5 x 1.7cm. Formed in mineralized veins of quartz, sulfides, wolframite, cassiterite, micas, fluorite, carbonates, among others, associated with the generation of a greisen dome by granite intrusion in Paleozoic schists and graywackes.