ɪn ˈælkəmi, tʃˈælkænθəm, ˈɔːlsoʊ kˈɔːld tʃˈælkænθ ɔːɹ kˈælkænθəm, wʌzɐ tˈɜːm jˈuːzd fɚðə kˈɑːmpaʊnd blˈuː vˈɪtɹiːəl kˈuː sˌoʊ fˈoːɹ, ænd ðɪ ˈɪŋk mˈeɪd fɹʌm ɪt.
In alchemy, chalcanthum, also called chalcanth or calcanthum, was a term used for the compound blue vitriol (CuSO4), and the ink made from it.