Zinc sulfide, ZnS, is an inert, odorless, gray-white to yellow powder. It is soluble in acid and denser than water. The compound decomposes at high temperatures and in oxidizing atmospheres, producing zinc and sulfur fumes. It is a fire and explosion hazard and will react with strong acids to liberate hydrogen sulfide, forming explosive mixtures in air. It is not toxic to humans, but may irritate the skin and eyes. Zinc sulfide is also hazardous to the environment, easily penetrating into the soil and contaminating groundwater. It has a low mohs hardness and can be used as a white pigment in paints, rubber and plastic.

It is an important raw material for the production of zinc salts, phosphors, and pigments, and as a reagent in the manufacture of many dyes. Its luminous properties make it useful in a number of applications, including as the phosphor in cathode ray tubes and in luminous paints. Its luminescence can be enhanced by doping with silver, copper or other elements.

The properties of zinc sulfide are heavily influenced by its surface. Surface hydration, surface adsorption of proton and hydroxide ions and redox reactions at the surface are important. The adsorption of these ions can be measured by performing acid base titrations on the suspension. The pH of the solution can then be correlated to the surface concentration of zinc sulfide, as shown in the graph below.