XL 3
This is an unusual specimen of Calcite from Dark Canyon in the Magdalena Mtns, New Mexico.  The Calcite crystals have a microcrystal coating of some sort that dims their fluorescence somewhat except for the tips, which creates an interesting visual texture.  Shown under shortwave UV.  Dimensions are 7 x 7 x 4 inches.  Weight is 14 lbs.  Price: $50.