Pyrites

pir-ī′tēz, n. a term applied to a large cla of mineral compounds of metals with sulphur, or with arsenic, or with both—crystalline, hard, generally brittle, and frequently yellow.— adjs. Pyritā′ceo us ; Pyrit′ic , -al ; Pyritif′erous .— v.t. Pyr′itise , to convert into pyrites.— n. Pyritol′ogy , knowledge of pyrites.— adj. Pyr′itous . [L.,—Gr. pyr , fire.]