The back of this large (for New York) sphalerite crystal is cleaved. You can easily see it when it turns in the movie. Despite this flaw, I think this is a wonderful specimen. Getting sphalerites of this size, on matrix, from Walworth is very difficult. This one presents so well, it is one of the best sphalerites I have seen from the quarry, even with the cleave in back. The matrix is dolomitic limestone, and the sparkle is from the druse of white dolomite rhombs covering the limestone. 3.8 x 3.1 x 2.2 cm.