Fluorite, Calcite, Chalcopyrite - Minerva #1 Mine, Cave in Rock, Illinois, USA
 
Well terminated, yellowish fluorite with chalcopyrite inclusions. The wonderful crystal has extremely interesting phantoms. In addition to chalcopyrite inclusions, calcite can also be found on the fluorite, which is partly speckled with purple dots.
The edges are highly lustrous and sharply terminated, while the surface of the slightly recessed inner surfaces (windows) is parqueted. The transparency of the outer edges form a "Mercedes Star" on the base
A wonderful collector's item from this site in the USA, which is famous for its outstanding fluorites.