The Colorado was originally mined for Lead, Silver, and Fluorine.  There I found pieces of Fluorite infused with surprisingly strong green Willemite, also phosphorescent. 


Colorado Mine 1 Colorado Mine 2


Nayal Black Hawk is a group of mines that encompasses an area of several small hills.  It was originally mined for Fluorine, Lead, and Silver.  Fluorite is indeed plentiful here and on the hillside I found some pieces just sitting on the surface, apparently not from any mining activity.  There were a wide variety of fluorescent minerals there including Hydrozincite, Calcite, Fluorite, Willemite, Hyalite, and Caliche.


Nayal Black Hawk Mine 1 Nayal Black Hawk Mine 2