A dramatic stairstep of sharp cubic crystals with octohedral edge modifications! This cluster is complete ALL AROUNDthe fluorite 100% present and accounted for even on the backside. There is some sulfide matrix attached. The specimen can go vertical, or horizontal as shown, or really from any other angle because its just as dramatic. I think it is a classical Naica piece with the more cubic style of crystallization, although the sphalerite association is unusual. The quality of the crystals is, in person, more transparent and more green in color than the washed-out gray you see here. A pastel green is more accurate