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

Dan Holtstam dan.holtstam at vr.se
Thu May 29 12:46:37 EDT 2014


clinochlore, kosmochlor does (normally) not contain Cl...

29 maj 2014 kl. 18:13 skrev "Alfredo Petrov" <alfredo at mindat.org<mailto:alfredo at mindat.org>>:

There are several examples of minerals named after an interesting element contained therein, with no requirement that said element must dominate the composition: Germanite, Stannite....


On 29 May 2014 07:12, John Schumacher <gljcs at bristol.ac.uk<mailto:gljcs at bristol.ac.uk>> wrote:
I have to say I did not realise titanite was an older name. That said, sphene is a better name in that it faithfully describes a common habit of the mineral; whereas, titanite is named after an element that composes only 33% of the ideal molecular oxides. Naming it after Si or Ca could have been equally appropriate.

John

Sent from my iPad, please forgive any typos

On 28 May 2014, at 22:24, Jerry Carter <jerry at jerrycarter.org<mailto:jerry at jerrycarter.org>> wrote:

Not that it will change your opinion in any way, but…

Titanite was first described by Martin Heinrich Klaproth in 1795 (Beiträge zur Chemischen Kenntniss der Mineralkörper).  The same species was rediscovered and named Sphene in 1801 by René Just Haüy.  There are many cases where species have had different names.  On my shelves, the Glossary of Obsolete Mineral Names lists some 30,000 terms which are no longer used.  It is something of an accident of history that the ‘titanite’ / ‘sphene’ camps were divided roughly evenly.  It was likely to happen to something and titanite / sphene isn’t the only case: just ask IUPAC about the sulphur / sulfur divide [1].  Here the loser receives some minor consolation as the mineral sulphur is composed of sulfur.

Best wishes,
Jerry

[1] http://www.nature.com/nchem/journal/v1/n5/full/nchem.301.html


On May 28, 2014, at 1:19 PM, Robert Tracy <rtracy at vt.edu<mailto:rtracy at vt.edu>> wrote:

Thanks for the support from sphene-thusiasts, both on the list and in private messages.

One of the reasons I am especially nostalgic about the name "sphene" is the possibility that this very nice word is also one of the roots of the English word "spoon", by way of many linguistic byways between Greek, old English, Old German and many others. Presumably this connection derives from the vaguely wedge-like shape a spoon has in profile. See the Wiktionary listing below:

spoon (n.)<http://www.etymonline.com/index.php?term=spoon&allowed_in_frame=0> [Look up spoon at Dictionary.com] <http://dictionary.reference.com/search?q=spoon>
Old English spon "chip, sliver, shaving, splinter of wood," from Proto-Germanic *spe-nu- (cognates: Old Norse spann, sponn "chip, splinter," Swedish spån "a wooden spoon," Old Frisian spon, Middle Dutch spaen, Dutch spaan, Old High German span, German Span "chip, splinter"), from PIE *spe- (2) "long, flat piece of wood" (cognates: Greek spathe "spade," also possibly Greek sphen "wedge").

Bob

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Associate Department Head
Director, Museum of Geosciences
Virginia Tech
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On May 28, 2014, at 3:33 AM, Dan Harlov wrote:

Here here Bob !!!

I have an avid dislike of that rather silly name titanite instead of using the much more atypical and more interesting name sphene.  Titanite would actually be a much more accurate name for rutile.   This is one of the few things that Eric Essene and I ever agreed on - I might note in passing.

In fact - I think the whole ' ite ' phenomena in naming minerals is greatly overblown.  Thank god these rules were not around when minerals such as quartz, spinel, and hornblende were being named !   At least we have some variety there.



On May 27, 2014, at 9:49 PM, Robert Tracy wrote:

Anachronism it may be in your opinion (and the IMA's) but I will resolutely continue to use the name Sphene whenever I am allowed to get away with it. The IMA has done some stupid things over the years (magnesian ferrosilite anyone?) but the outlawing of the beautiful (and unambiguous) name Sphene is top of my list.

Dr. Robert J. Tracy
Prof. of Geosciences
Associate Department Head
Director, Museum of Geosciences
Virginia Tech
Blacksburg VA 24061-0420
540-231-5980<tel:540-231-5980>
540-231-3386<tel:540-231-3386> (F)




On May 27, 2014, at 11:28 AM, Anton Chakhmouradian wrote:

For all purposes, MgO with subordinate Fe in the lower mantle IS periclase (its rock-salt structure is very robust and persists to > 200 GPa; Duffy et al., Phys. Rev. Let., 74, 1371). At ambient conditions, FeO is isostructural with periclase and known as the mineral wüstite (in addition to metallurgical slags, it occurs in meteorites and a few obscure terrestrial environments). The intermediate Mg-dominant members should then be termed Fe2+-rich (-bearing) periclase, according to the IMA guidelines. The rock-salt structure of FeO transforms into a rhombohedral polymorph at 18 GPa, but the presence of Mg seems to stabilize the rock-salt arrangement throughout the lower-mantle P range (see, e.g., Lin et al., PNAS, 100, 4405). That means that, from the standpoint of nomenclature, we are dealing with compressed intermediate members of the periclase-wüstite series. Any other name applied in the literature (magnesiowüstite, ferropericlase, ferroan periclase, etc.) is not in accord with the IMA recommendations. Of course, people still use this “illegal” terminology, just like one can still bump into sphene, melanite, picroilmenite and numerous other anachronisms in the Min-Pet literature.

Anton Chakhmouradian
University of Manitoba


From: msa-talk-bounces at minlists.org<mailto:msa-talk-bounces at minlists.org> [mailto:msa-talk-bounces at minlists.org] On Behalf Of Charles Carrigan
Sent: Tuesday, May 27, 2014 9:56 AM
To: David Hirsch; MSA-talk (msa-talk at minlists.org<mailto:msa-talk at minlists.org>)
Subject: Re: [MSA-talk] Mineral name for perovskite-structured (Mg, Fe) silicate?

How about MgO with rock-salt structure referred to as “magnesiowustite”?  I’ve even seen a reference to FeO as “ferropericlase”.


Best,
Charles

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From: msa-talk-bounces at minlists.org<mailto:msa-talk-bounces at minlists.org> [mailto:msa-talk-bounces at minlists.org] On Behalf Of David Hirsch
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

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Daniel Harlov
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Daniel Harlov
Section 3.3 Chemistry and Physics of Earth Materials
Helmholtz-Zentrum Potsdam
Deutsches GeoForschungsZentrum - GFZ
Stiftung des öff. Rechts Land Brandenburg
Telegrafenberg
D-14473 Potsdam
FR Germany

international tel +49 (331) 288-1456<tel:%2B49%20%28331%29%20288-1456>
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email: dharlov at gfz-potsdam.de<mailto:dharlov at gfz-potsdam.de>












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