Wilhelm Karl Ritter von Haidinger (or Wilhelm von Haidinger, or most often Wilhelm Haidinger) (5 February 179519 March 1871) was an Austrian mineralogist. Early life Haidinger's father was the mineralogist Karl Haidinger (1756–1797), who died when Wilhelm was only two years old. The books on mineralogy and the collection of rocks and minerals of his father will almost certainly have raised the interest of young Wilhelm. The collection of his uncle, banker Jakob Friedrich van der Nüll, was by far larger and much more precious, even to such a degree that the famous professor Friedrich Mohs of Freiberg (Germany) had been asked to describe it in detail. Young Wilhelm Haidinger and the professor often met in the house of Wilhelm's uncle. After completing the "Normalschule" and the "Grammatikalschule" Wilhelm started out his pre-academical training at the local "Gymnasium". However, after completing only his first year, the "Humanitätsclasse", Wilhelm (now 17 years old) was asked by professor Friedrich Mohs to join him as his assistant at the newly founded Universalmuseum Joanneum in Graz. Scientific career During the next five years in Graz and the following six years in Freiberg Wilhelm Haidinger remained a devoted assistant and admirer of professor Friedrich Mohs. During these years Haidinger became more and more involved in scientific work. In 1821 Wilhelm Haidinger published his first scientific paper: "On the crystallisation of copper-pyrites" in the Memoirs of the Wernerian Natural History Society (Edinburgh), volume 4, pp. 1–18. This paper formed the start of a grand total of some 350 scientific publications, all of which are listed in volume 3 of the Catalogue of Scientific Papers (1800–1863) and volume 10 of the same catalogue for the years 1864–1883. Apart from all these papers Wilhelm Haidinger published several books: Anfangsgründe der Mineralogie, an account on the collection of the "k. k. Hofkammer im Münz- und Bergwesen"; a review of mineralogical research (which grew into a well-known series edited by Gustav Adolph Kenngott); his Handbuch der bestimmenden Mineralogie; an atlas to this textbook on mineralogy and the first complete geological map of Austria-Hungary. In 1822 Wilhelm Haidinger accompanied August Graf von Breunner-Enckevoirt (1796–1877) on a six-month trip; they traveled from Linz to Munich, Basel, Paris, London and Edinburgh. In Edinburgh banker Thomas Allan provided Haidinger with the means to translate Mohs' Grundriss der Mineralogie into English. (The translation appeared in 1823 in three volumes: Treatise on Mineralogy.) In 1823 Wilhelm