CaS, or Calcium Sulfide, is a chemical compound made up of calcium and sulfur. It is often found in nature as a mineral and can also be produced synthetically. CaS is known for its use in various applications, including as a phosphor in lighting and as a precursor for other chemical compounds. In addition to its industrial uses, Calcium Sulfide has applications in agriculture, where it can help improve soil quality. It is also used in the production of certain types of glass and ceramics, showcasing its versatility in different fields.