Oellacherite

Named in 1867 by James Dwight Dana in honor of Josef Oellacher [February 16, 1804 Pressburg, Austria - August 16, 1880 Innsbruck, Austria], a chemical pharmacist who first investigated a similar mineral (Oellacher, 1862) and thought it was margarite. The original oellacherite was from Kemmat, Sterzing (Vipiteno), Vizze Valley (Pfitsch Valley), Bolzano Province (South Tyrol), Trentino-Alto Adige, Italy. Because true margarite was discovered near Mt. Grenier, about 19 km distant from the oellacherite locality, there was some confusion that the two micas might be equivalent. Oellacher's (1862) chemical analysis was clearly not consistent with margarite (Des Cloizeaux, 1867), but it was unusual in its chemistry containing Ba, Na, Ca, etc. Des Cloizeaux's specimens were sent to him by Karl Rammelsberg labeled "Baryt-glimmer" and their optic properties seemed more consistent with muscovite. The chemical anomaly prompted Dana to re-name the species oellacherite. In 1933, Lawson H. Bauer and Harry Berman studied "oellacherite" from Franklin, New Jersey, USA, and re-named it, "barium muscovite", for its chemical relationship to muscovite, but the mineral studied was not Ba-dominant, either, although it too had anomalous chemical and physical properties.