Orpiment is a bright yellow mineral composed of arsenic sulfide, with the chemical formula As2S3. It is often found in hydrothermal veins and is known for its vibrant color, which has made it historically popular as a pigment in art and decoration. Due to its arsenic content, orpiment is toxic and should be handled with care. It has been used in traditional medicine and alchemy, but its use has declined due to safety concerns. Today, orpiment is primarily of interest to mineral collectors and researchers studying arsenic minerals.