Michael S. Rumsey, Owen P. Missen, Stuart J. Mills
Abstract Montanite, named by Frederick August Genth over 150 years ago for the Montana Territory was the world’s first naturally occurring tellurium oxysalt, but was designated ‘Q’ (questionable) by the IMA-CNMNC until our study in 2022. Like many minerals described in the 19 th century it had no designated type specimen. Interrogation of institutional archives, contemporaneous publications and specimen labels reveals three distinct early occurrences, two of which are interpreted as co-type localities. In lieu of being able to conclusively identify or access the original type specimens for research, suitable surrogates were defined as neotypes that respected the historical precedence of the initial discoveries enabling montanite to be formally established as a mineral species. Especially for this historically themed edition of Mineralogical Magazine , this paper presents the process and a case-study of the historical research and decision-making required for new minerals, redefinitions or discreditations that are often out-of-scope of the academic journals that publish the resulting scientific research.