Sphalerite is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides along with calcite, dolomite, and fluorite. Miners have also been known to refer to sphalerite as zinc blende, black-jack, and ruby jack.
GLOW POWDER is zinc sulfide - not as cheap as breaking open a glow stick, but a whole lot safer! "It glows an eerie green light when the lights go off. Our team of creative teachers packed the included activity guide with a bunch of great ideas... from glowing alien blobs to glow-in-the-dark putty." link goes to SteveSpanglerScience - check out the blog as well as the catalog.