About
矸 (gān) is a phono-semantic compound used in geology and mining to denote gangue, the commercially worthless rock mixed with ore. Its structure combines the semantic radical 石 (shí, "stone"), indicating the material's physical nature, with the phonetic component 干 (gān), which guides pronunciation. Historically, the character has served to distinguish excavation waste from valuable coal or mineral deposits. It commonly appears in the compound 煤矸石 (méigānshí), referring specifically to waste rock from coal mining.