As late as 1781 James Price claimed to have produced a powder that could transmute mercury into silver or gold.
æz lˈeɪt æz wˈʌn θˈaʊzənd sˈɛvənhˈʌndɹɪd ˈeɪɾi wˈʌn dʒˈeɪmz pɹˈaɪs klˈeɪmd tə hæv pɹədˈuːst ɐ pˈaʊdɚ ðæt kʊd tɹænsmjˈuːt mˈɜːkjʊɹi ˌɪntʊ sˈɪlvɚ ɔːɹ ɡˈoʊld.