Antimony sulfide (Sb 2 S 3 ), the principal ore of antimony .
This sulfide mineral has a brilliant metallic lustre, is lead or steel gray in colour, and fuses (melts) readily. Stibnite occurs in low-temperature hydrothermal veins (see hydrothermal ore deposit s) and in replacement deposit s. Significant deposits have been found in China, Japan, and the U.S. (Idaho, California, and Nevada). Stibnite is used in making matches, fireworks, and percussion caps and was used by the ancients as a cosmetic (called kohl) to increase the apparent size of the eye.