Copper sulfide (CuS) can appear in a variety of colors depending on its specific composition and crystal structure. However, the most commonly observed colors of CuS are black, gray, dark blue, and dark red.

The black coloration is often associated with the mineral covellite, which is a monoclinic form of copper sulfide. Chalcocite, another monoclinic form of CuS, can appear in various shades of gray and dark blue. When copper sulfide is present as the mineral djurleite, it can exhibit a dark red color.

It's important to note that the color of CuS might also be influenced by the presence of other elements, impurities, or the oxidation state of copper in the compound.