From: Panasqueira Mine, Covilhã, Castelo Branco, Portugal.
 
 
Green grey translucent hexagonal prisms with aprox. 2,0-2,5cm. Formed in mineralised veins of quartz, sulfides, wolframite, cassiterite, micas fluorite, carbonates, among others, associated with the generation of a greisen dome by granitic instrusion in Paleozoic shales and graywackes.