Phosgenite

A complex large crystal, almost 6 cm long, of glassy Phosgenite with a ferruginous matrix attached.  What appears to be damage are areas of growth interference with the matrix, resulting in several glassy, mirror-bright plateaus interrupted by crevasse-like depressions, themselves lined with later generation millimetre-sized Phosgenite crystals.  This specimen is from the world famous Monteponi mine at Iglesias on the Italian island of Sardinia.  The specimen displays good levels of transparency; mirror bright prism faces and mirror-smooth prism faces while being, contradictory, heavily striated.  It comes with a handwritten old label and a U.S. National Museum (Division of Mineralogy) label.