Wikipedia
Zinc sulfide
Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment. In its dense synthetic form, zinc sulfide can be transparent, and it is used as a window for visible optics and infrared optics.
Usage examples of "zinc sulfide".
Instead of being activated by light, zinc sulfide crystals are stimulated by alpha rays, supplied by trace amounts of radium -- no more than two parts per million -- mixed into the pigment compounds.