Sphalerite from the Horn Silver Mine in Utah is some of the more interesting material around. Stunning in longwave, bright and colorful phosphorescence, and extreme triboluminescence. The first image shows the triboluminescence, where a mineral gives off light as it is broken apart. In this case, I used a long exposure while I scratched the surface with a metal point. In several areas, small sparks can be seen flying off the rock. The second photo shows the longwave response. The third image shows the two color phosphorescence. And the final image is the rock in natural light; who could tell that such a nondescript rock could hide such beauty.