Watch a video of this specimen by following the Vimeo link below: https://vimeo.com/1144437059/01bed95164 Here is an absolutely remarkable specimen from the famous Tri-State district (Picher Field), displaying fairly big polysynthetic crystals of sphalerite, decorated with sparkling micro epitaxial chalcopyrite. The matrix is a silicified limestone coated in micro quartz and you can note some late generation, very gem red 'ruby jack' sphalerite crystals on it! Ex collection Koch (Belgium).