[MSA-talk] Mineral name for perovskite-structured (Mg, Fe) silicate?
Anton.Chakhmouradian at umanitoba.ca
Tue May 27 22:54:45 EDT 2014
Getting back on the topic of perovskite-type (Mg,Fe)SiO3 and CaSiO3. To name (Mg,Fe)SiO3 after Lin-gun Liu seems like the most appropriate thing to do, of course, but Fredrik William H. Zachariasen certainly deserves one of the future perovskites to be named after him, as well, for his instrumental role in deciphering the structural relations between perovskites and other complex ABO3 oxides under Goldschmidt's tutelage. Thomas Barth was actually the first to publish the structure of CaTiO3, but there is already a TOMBARTHITE (monazite-type hydrous Y silicate). Zachariasen came up with the now-fundamental tolerance factor concept. Here is some bio information on him for anyone interested:
Incidentally, anyone fascinated by perovskites (or the history of mineralogy) may be interested in reading our editorial in the PCM thematic issue on these minerals:
Anton R. Chakhmouradian
University of Manitoba
Sent: Tuesday, May 27, 2014 9:31 AM
To: MSA public List serve
Subject: [MSA-talk] Mineral name for perovskite-structured (Mg, Fe) silicate?
I’ve just read a news release online about the new Zhang, et al. Science paper "Disproportionation of (Mg,Fe)SiO3 perovskite in Earth’s deep lower mantle”. Is there a mineral name for the perovskite-structured (Mg,Fe)SiO3 mineral? If not, then shouldn’t we come up with one? It seems to me that the name “perovskite” should apply to the CaTiO3 mineral, and that it’s wrong to apply it to the isostructural silicate, just as we don’t give the same mineral name to halite and galena. The article title isn’t so bad, but when you get news releases that include this kind of thing, then there’s a real problem:
"The prevailing theory has been that the majority of the lower mantle is made up of a single ferromagnesian silicate mineral, commonly called perovskite (Mg,Fe)SiO3) defined through its chemistry and structure. It was thought that perovskite didn't change structure over the enormous range of pressures and temperatures spanning the lower mantle”
The release’s author here has presumably misinterpreted the article’s title to infer that “perovskite" is the name of the mantle mineral, rather than "(Mg,Fe)SiO3 perovskite”, indicating a perovskite-structured silicate.
I understand that an official mineral name is not possible, since it cannot be found occurring naturally and fully described, but perhaps if the community decided on a name we could use in lieu of the (to me) troubling "(Mg,Fe)SiO3 perovskite” or worse “perovskite”, then there might be a little more clarity and a little less confusion out there, at least among mineralogy students.
Department of Geology
Western Washington University
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