Sphalerite     Elmwood Mines, Carthage, Tennessee.  This quartz coated limestone plate measures 13 x 7 x 3 cm and has numerous twinned and non-twinned sphalerite crystals to 1.7 cm each.  Only one of the smallest crystals shows a small area on its side that is cleaved.  The piece is a floater and displays nicely in any position.  $50