Tellurium was discovered by Franz Joseph Müller von Reichenstein, a Romanian mining official, in 1782. Reichenstein was the chief inspector of all mines, smelters and saltworks in Transylvania. He also had an interest in chemistry and extracted a new metal from an ore of gold, known as aurum album, which he believed was antinomy. He shortly realized that the metal he had produced wasn't antimony at all, but a previously unknown element. Reichenstein's work was forgotten until 1798 when Martin Heinrich Klaproth, a German chemist, mentioned the substance in a paper. Klaproth named the new element tellurium but gave full credit for its discovery to Reichenstein. Tellurium is found free in nature, but is most often found in the ores sylvanite (AgAuTe4), calaverite (AuTe2) and krennerite (AuTe2). Today, most tellurium is obtained as a byproduct of mining and refining copper.