Very reflective metal-like crystal, or a nondescript grayish powder. m.p. 449.5±0.3 ºC; 841.1±0.5 ºF b.p. 989.8±3.8 ºC; 1813.6±6.8 ºF density 6.24 g/cc; 389.55 pound/cubic foot	memory peg
	1782 Franz Joseph Müller von Reichenstein, Austria
	tellus = the Earth (Latin) Named by Martin H. Klaproth in 1798

Tellurium was discovered in a certain gold ore from Transsylvania. This ore, known as "Faczebajer weißes blättriges Golderz" (white leafy gold ore from Faczebaja) or "antimonalischer Goldkies" (antimonic gold pyrite), was according to professor Anton von Rupprecht "Spießglaskönig" (argent molybdique), containing native Antimony (note). The same ore was analyzed by by Franz Joseph Müller Freiherr von Reichenstein (1742-1825) (note), chief inspector of mines in Transsylvania, he concluded in 1782 that the ore did not contain Antimony, but that it was Bismuth sulphide (note). A year later he reported that this was erroneous and that the ore contained mainly gold and an unknown metal very similar to Antimony (note). However, Müller was not able to identify this metal. He gave it the name aurum paradoxium or metallum problematicum because it did not show the properties predicted for the Antimony he was expecting.

Müller sent samples to Torbern Bergman (1735-1784) for further analysis, but he died before he could do further analysis. Twelve years later, Müller, still searching for the new metal, sent a specimen to Martin Heinrich Klaproth (1743-1817). He succeeded and confirmed the discovery of the new metal. In his paper before the Academy of Sciences of Berlin of 25 January 1798 he gave the metal the "von der alten Mutter Erde entlehnten" name Tellurium, that derives of Latin tellus = Earth:

and in the French translation:

(Cf. Selenium).

In his 1798 report Klaproth gave full credit to the original discoverer, Müller von Reichenstein, but forgot to mention the Hungarian chemist Paul Kitaibel (1757-1817), who in 1789 had independently discovered the new metal and had sent his report to Klaproth.

Kitaibel had in 1789 found the new element in an ore from Deutsch-Pilsen (Börzseny), which was considered to be molybdic silver (argentiferous molybdenite). Later, he also analyzed Müller's aurum problematicum and found that it contained the same new element. His report handed over to Klaproth, when he visited Vienna in 1796, who gave him a most favorable written report. He obviously forgot the whole matter or did not notice that it concerned the same metal, when he reported on Müller's metal.

• At the occasion of the 250th anniversary of Müller's birth the Montanhistorische Verein für Österreich (MHVÖ) organized on 23 and 24 September 1992 a symposium in Polysdorf, with the theme: "Franz Josef Müller von Reichenstein und das Montanwesen in der 2. Hälfte des 18. Jahrhunderts". The proceedings were published in the 1992 issue of their journal Res Montanarum. Several contribution are devoted to the discovery of Tellurium.

  Table of contents (click on the cover for the website).

  Simone und Peter HUBER: Die Medaille aus Nagyager Tellur Erich SCHROLL und Diets SAUER: Tellur in Natur und Technik Diets SAUER und Erich SCHROLL: Tellur und Medizin Ferenc SZABADVARY: Die Entdeckung des Tellurs Istvan TRINGLI: Franz Joseph Müller als bekannter und unbekannter Wissenschafter Simone und Peter HUBER: Franz Joseph Müller Freiherr von Reichenstein – seine Bedeutung für die Mineralogie und seine Veröffentlichungen Joseph PEYER: Franz Joseph MÜLLER – Vorfahren und Kindheit Georg MUTSCHLECHNER: Franz Joseph Müller in Tirol (1775 – 1778) Ion DORDEA: Aus dem Leben und Wirken des Gubernialrats Franz Joseph Müller von Reichenstein als Leiter des Siebenbürgischen Bergwerksthesauriats in den Jahren 1778 – 1802 Jozef VOZAR: Franz Joseph Müller in der Slowakei Alfred WEISS: Die Entwicklung des k.k. Montanwesens im 18. Jahrhundert Jozef VOZAR: Das Schemnitzer Bergwesen und die Gründung der Bergakademie

• Tellur. Gmelins Handbuch der anorganische Chemie, 8. Aufl.; System-Nummer 11 (1940).
• Mary Elvira Weeks, Discovery of the Elements, comp. rev. by Heny M. Leicester (Easton, Pa.: Journal of Chemical Education, 1968), pp. 289-305.