Calcite crystals in modified rhombs from the Fluorospar region of Illinois. These are dusted with sparkling crystals of Chalcopyrite and have an epitaxial alignment. In very good condition, most of the crystals are perfect and damage-free. The specimen has a small break on the underside where it was removed and some tiny rough spots (.5 mm) are seen with a loupe. An old label from Ross Lillie (North Star Minerals) is with this piece.