This is what I'd call "crazy" or "swirly" willemite, in a matrix of calcite (red) and franklinite (non-fluorescent).  I'd compare this material with the proverbial "explosion in a paint factory". I wonder what geologic process might have yielded this stuff! The picture is pretty bright, but it's no match for how intense this material looks in real life-- even under the smallest of shortwave lamps. I found this one on the Mine Run Dump at Sterling Hill, where the Hauck brothers put tons of ore they rescued from the advancing floodwaters of the Sterling Mine. Many of the rocks on the Mine Run Dump contain vastly more willemite than calcite, because these are high-grade ore rocks that actually would have been processed to get the zinc, had the mine not closed.  Anyway, the goal is to look for a good balance of the calcite vs. willemite. Because its fluorescence is so bright, willemite tends to look overexposed in any photographs I try to take of it. Specimen is large, about 7 inches across. Site contents copyright 2005, C. Thorsten