Stibnite is a mineral composed of antimony sulfide, with the chemical formula Sb2S3. It typically appears as a gray to black, metallic-looking crystal and is known for its elongated, prismatic shapes. Stibnite is often found in hydrothermal veins and can be associated with other minerals like quartz and pyrite. This mineral is primarily mined for its antimony content, which is used in various applications, including flame retardants, batteries, and alloys. Stibnite has a relatively low hardness on the Mohs scale, making it easy to scratch, and it can be identified by its distinctive metallic luster and cleavage.