[MSA-talk] Mineral name for perovskite-structured (Mg, Fe) silicate?

Anton Chakhmouradian Anton.Chakhmouradian at umanitoba.ca
Wed May 28 16:14:09 EDT 2014


It is a bit “unfortunate” that LINGUNITE is already taken (thank you, Thomas, for “chiming in”). So is BIRCHITE, actually (Ca-Cd phospho-sulfate), but named after William Birch of Victoria Museum. There has been a very good succinct retrospect published on mineral physics in Sciences of the Earth (ed. by Good, 1998); see under “Matter, Properties...”  (pp. 523-535). Plenty of deserving people have not been “mineralized” yet!

Anton Chakhmouradian
University of Manitoba

From: Frank Spera [mailto:spera at geol.ucsb.edu]
Sent: Wednesday, May 28, 2014 10:51 AM
To: Thomas Sharp
Cc: Anton Chakhmouradian; msa-talk at minlists.org
Subject: Re: [MSA-talk] Mineral name for perovskite-structured (Mg, Fe) silicate?

Call it birchite unless already used to honor the guy who more or less started mineral physics based on Bridgman foundations
Fs

Sent from my iPhone

On May 28, 2014, at 12:14 AM, Thomas Sharp <tom.sharp at asu.edu<mailto:tom.sharp at asu.edu>> wrote:
Hi All

I was too busy this morning to chime in, but I would like to add a few things.

(Mg,Fe)SiO3-perovskite, like all deep mantle minerals do occur naturally in highly shocked meteorites.  Tomioka and Fujino (1997, Science) found some that had formed from enstatite in a shock vein in Tenham. At the same time, Sharp et al (1007 Science) found some pyroxene-composition glass grains that we interpreted as (Mg,Fe)SiO3-perovskite that crystallized from the silicate melt. Unfortunately, Tomioka did not have enough material to get sufficient diffraction data and the material I found had transformed to glass in the relatively high temperature post-shock environment. I have been looking in other highly shocked meteorites to find crystalline silicate perovskite.Recently, Miyahara et al (2011 PNAS)  found olivine that transformed to (Mg,Fe)SiO3-perovskite plus magnesiowustite in a shocked martian meteorite, but they had very little crystalline material. There may be some XRD data on natural (Mg,Fe)SiO3-perovskite soon.

When this important compound is given a mineral name, it won't be named after Lin-gun Liu because NaSi3AlO8-hollandite has already been named Lingunite. It will be interesting to see what name is given to one of the most abundant compounds in the earth.

Sincerely,


Thomas Sharp
Director, LeRoy-Eyring Center for Solid State Science
Professor, School of Earth and Space Exploration
tom.sharp at asu.edu<mailto:tom.sharp at asu.edu>


Thomas Sharp
Professor, School of Earth and Space Exploration
Director, LeRoy-Eyring Center for Solid State Science
Director, ASU/NASA Space Grant Program
tom.sharp at asu.edu<mailto:tom.sharp at asu.edu>

From: Anton Chakhmouradian <Anton.Chakhmouradian at umanitoba.ca<mailto:Anton.Chakhmouradian at umanitoba.ca>>
Date: Tuesday, May 27, 2014 7:54 PM
To: "msa-talk at minlists.org<mailto:msa-talk at minlists.org>" <msa-talk at minlists.org<mailto:msa-talk at minlists.org>>
Subject: [MSA-talk] Mineral name for perovskite-structured (Mg, Fe) silicate?


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:



http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/zachariasen-frederik.pdf

https://www.fas.org/sgp/othergov/doe/lanl/pubs/00818116.pdf



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:



http://link.springer.com/article/10.1007%2Fs00269-014-0678-9





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?

Friends-
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.
-Dave

============================
Dave Hirsch
Associate Professor
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Western Washington University
alternate email: dhirsch at mac.com<mailto:dhirsch at mac.com>
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