MOHS' OR WERNER'S HARDNESS SCALE: WHO SHOULD GET THE CREDIT?

Comparison of the original writings of Abraham Gottlob Werner and Carl Friedrich Christian Mohs reveals many similarities in the relative hardness scale of minerals developed by each. Werner (1774) discussed the use of hardness as a tool for mineral classification and proposed a relative hardness scale in his Treatise on the External Characters of Fossils. Werner’s relative hardness scale was published when he was twenty-four years old, before he became a professor at the Bergakademie in Freiberg, Germany. Werner became one of the most famous “geologists” of the period, and was extremely influential in educating many of the “early” developers of modern geological theory. Many of Werner’s students were publishing materials from his lectures without permission, which angered him even into his later years because his former students were “robbing his authorship”. Friedrich Mohs was one of Werner’s pupils. After Werner died in 1817, Mohs was asked to fill Werner’s position as professor at the Bergakademie in Freiberg. Mohs (1824) elaborates his hardness scale in The Treatise on Mineralogy, or the Natural History of the Mineral Kingdom for which Mohs is given credit for inventing the hardness scale. Both the methodologies for determining hardness as well as the scale itself as elaborated by Mohs are eerily similar to Werner's methodologies and scale. Werner’s hardness scale has a greater number of minerals than Mohs and is divided into seven major categories. Mohs’ scale uses most of the same minerals that Werner used in his scale. One of the major differences between the two is that Mohs’ scale is exactly inverted (soft to hard) from Werner's “hard to soft” version. Mohs also simply divided a couple of Werner’s categories. Mohs was not a newcomer to using the work of others for his own benefit and had a history of publishing new similar systems that others had developed, which included public accusations of plagiarism in reference to another mineralogy book that Mohs’ authored.