Calcite, Pyrite and Marcasite      Conco Mine, North Aurora, Kane County, Illinois.  Collected by Jared T. Freiburg.  A single pocket find that was harvested just prior to the 2011 Tucson show.  Very nice material!  Selective face coatings make some areas of the crystals look silky while others have the highest, glassy luster anyone could ask for in a calcite.  Reminiscent of the Brushy Creek material but finer.  The marcasite and pyrite are bright metallic inclusions that sometimes zone as phantoms.  Really nice stuff.  This cluster measures 11.2 x 7.5 and is a thin plate of well formed, damage-free crystals to over 3 cm each.  Some are doubly-terminated but most are singly-terminated.  Very fine example that is not quite as high in luster as some of the very best from the find.  No damage.    $95