Hi Bela,

there are some mineral names that are approved (only name approved). They are amphiboles and they was approved by the previous Amphibole Subcommittee, 1997.

If all data in my database are correct also the following "minerals" are only semi-approved (in my database status S for "semi-approved"):


S Aluminobarroisite

S Alumino-ferrobarroisite

S Alumino-ferrotschermakite

S Aluminokatophorite

S Aluminotschermakite

S Cannilloite

S Clinoferriholmquistite

S Clinoferroholmquistite

S Ferribarroisite

S Ferri-ferrotschermakite

S Ferritschermakite

S Ferro-eckermannite

S Ferroleakeite

S Ferronybøite

S Ferrowinchite

S Ottoliniite

S Pedrizite

S Permanganogrunerite

S Potassic-aluminosadanagaite

S Potassichastingsite

S Sodic-ferropedrizite

S Sodicpedrizite


Probably the present Amphibole Subcommittee sort out the problem.

Ciao. Marco

I can't see how these can be regarded as valid mineral species. There are plenty of other theoretical end members that have not yet been found in nature which don't have valid species status.


Maybe there needs to be a distinction between an approved NAME and an approved mineral species.


The name could be approved when talking about amphibole compositions (if that's really necessary, why not just talk about them in terms of chemical composition), but NOT as a valid species.


No specimen = no species in my mind.

I have pictures of three of these

Aluminotschermakite - http://www.mindat.org/min-450.html

Ferri-ferrotschermakite = Ferro-ferritschermakte - http://www.mindat.org/min-1460.html

Ferro-eckermannite - http://www.mindat.org/min-1465.html


I would be appreciative if someone can straighten out this mess - the problem is more general, in that species get redefined, and garner an 'approved' status, without ever having a formal description

Type descriptions are inexistent, but a part of the "minerals" listed were found in nature (EPMA results). I sent some specimens to Giancarlo Della Ventura and/or Roberta Oberti that are members of the new Amphibole Subcommittee.

Bela,


you can find analytical data on sodicgedrite and sodic-ferrigedrite and other Amphiboles in:


Deer, Howie, Zussmann (1997): Rock-forming minerals, Volume 2B, Double-chain Silicates, second edition, Geological Society, London.


Christof

Following is my information about the six amphiboles queried by Bela:


Sodicanthophyllite: Name approved by the IMA (Can. Mineral. 35 (1997), 219, but no description published yet.


Sodic-ferro-anthophyllite: ditto


Sodic-ferrogedrite: Name also approved in 1997. A description of a mineral that corresponds to the definition of this species can be found in DHZ, 2nd ed. (1997), Table 2, analysis 17.


Sodic gedrite: Name also approved in 1997. A description of a mineral that corresponds to the definition of this species can be found in DHZ, 2nd ed. (1997), Table 2, analyses 13, 14 and 16.


Sodic-ferropedrizite: Name approved by IMA as IMA 1998-061. Full description published in Am. Mineral. 85 (2000), 578.


Sodicpedrizite: Name approved by IMA (Can. Mineral. 41 (2003), 1355, but no description published yet.


Cheers, Ernie...

From the Marco list I have Ferroeckermannite, Ferronyböite, Ferrowinchite and Potassichastingsite from 4 different dealers and one expert. Are they all false specimens?

Hans Kloster Wrote:

-------------------------------------------------------

> From the Marco list I have Ferroeckermannite,

> Ferronyböite, Ferrowinchite and

> Potassichastingsite from 4 different dealers and

> one expert. Are they all false specimens?


Probably not. Perhaps that they are valid... but it is not so easy correctly characterize and normalize the amphiboles.

Oh, these amphiboles and their names!

Ernie, the amphibole with IMA no. 98-061 published in Am. Mineral. 85 (2000), 578-585 is NOT sodic-ferropedrizite, BUT sodic-ferripedrizite.

All six sodic amphiboles mentioned by Bela (sodicanthophyllite, sodic-ferroanthophyllite, sodic-ferrogedrite, sodicgedrite, sodic-ferropedrizite and sodicpedrizite) are theoretical end members which were given a name in amphibole nomenclature reports.

The qualification "semi-approved" as used by Marco is a bit misleading, only a name has been given in case of their appearance some day; "theoretical" would be a better qualification until that time.

Ernst A.J. Burke Wrote:

-------------------------------------------------------

> Oh, these amphiboles and their names!

> Ernie, the amphibole with IMA no. 98-061 published

> in Am. Mineral. 85 (2000), 578-585 is NOT

> sodic-ferropedrizite, BUT sodic-ferripedrizite.

> All six sodic amphiboles mentioned by Bela

> (sodicanthophyllite, sodic-ferroanthophyllite,

> sodic-ferrogedrite, sodicgedrite,

> sodic-ferropedrizite and sodicpedrizite) are

> theoretical end members which were given a name in

> amphibole nomenclature reports.

> The qualification "semi-approved" as used by Marco

> is a bit misleading, only a name has been given in

> case of their appearance some day; "theoretical"

> would be a better qualification until that time.



OK, I agree with "theoretical end member". Thanks Ernst.

Thank you for the answers. I totally agree with Jolyon that there needs to be a distinction between an approved name (if only the name is approved!) and an approved mineral species. I will check Ernie's data in DHZ.

We do have a mindat IMA classification of "hypothetical" which should be used for these types of approved names where natural material has not been found.

Yes Dave I think that it is a good solution: the unique difference is that the name, in these cases, was regularly approved.

I agree with David that the status "H" (for "hypothetical") should be applied to mineral names that have been approved but for which no descriptions have been published, and I will do this in my working database. Eventually this will show up in the IMA list and in the version of MINERAL distributed by MDI. In the meantime I will compile a list of such mineral names and send them to Jim Ferraiolo in the expectation that he will make the necessary status changes in Mindat.


Thanks for the correction, Ernst. Sodic-ferropedrizite is another of the approved names without a published description, hereafter with "H" status.


Cheers, Ernie...

Hans:


I can give you a bit of information about the 4 amphiboles in your message:


Ferronyböite: Description not yet published; status "H".


Ferro-eckermanite: Description in DHZ, 2nd ed. (1997), vol. 2B, Table 31, analysis 6.


Ferrowinchite: Description in DHZ, 1st ed., vol. 2 (1963), p. 352.


Potassichastingsite: Description in DHZ, 2nd ed. (1997), vol. 2B, Table 15



Cheers, Ernie...

With regard to my previous message, I must point out that the name nybøite and its various derivatives should be written with the alphabetical symbol "ø", not "ö", as reported in the recent paper by Ernst Burke in Min. Rec. 39 (2008), 131-135.


Ernie...

Ernie's list has been added or corrected.

Note that Mindat has the option to choose "hypothetical" as IMA approval status.

Aluminotschermakite is one of Uwe's "semi-approved" amphiboles. It is also IMA-approved and you might expect it to therefore be a "hypothetical" species. However, amphibole with the composition of aluminotschermakite is reported in Zenk & Schultz 2004 Zoned Ca-amphiboles and related P-T evolution in metabasites from the classic Barrovian metamorphic zones of Scotland. Min. Mag. 68, 769-786.

As far as I know this "species" has never been formally described - so what is it? - "semi-approved", "hypothetical", "confirmed species" or something else?

With the amphibole group also host to "named species" (Burke & Leake 2005 Amer Mineral. 90, 516-517), perhaps it should have this status?


I'm also aware of published data for aluminokatophorite and ferrowinchite.


In my mind "hypothetical" means "not found in nature" - so how can "species" like "potassichastingsite" (data reported in DH&Z) be given H status?

All,


There is also a amphibole subcommittee working at the moment and allot of this might be cleared up.


Stu

This is probably a text book example why the CNMNC discourages the publication of a mineral name before there is a published description of the mineral from a type locality.

Hi, Andy:


Hopefully Stu is right, and some of amphibole nomenclature might get cleared up by the current Amphibole Subcommittee. However, my take on aluminotschermakite is that the name was approved by the IMA, and an analysis corresponding to the definition can be found in DH&Z, 2nd ed., vol. 2B (1997), Table 12, analysis 10. Therefore I think that the status "A" (Approved) is probably appropriate.


Regarding potassichastingsite, several descriptions have been published under various names, including potassium hastingsite, magnesian postassium-hastingsite and magnesian potassic hastingsite. In my database, which forms the basis of the IMA Mineral List, the mineral has Rn (Revised Name) status because the name potassichastingsite was formally approved by the IMA.


Aluminokatophorite presents a different problem. The name was included in the 1978 Amphibole Report, but missing from the 1997 report. Does that mean that approval has been rescinded? It's hard to say, so I have given it "Q" (Questionable) status in my database.


As you can see, it is not always easy to provide adequate information by the use of a simple status symbol. Perhaps we will get some guidance in the next report of the Amphibole Subcommittee.


Cheers, Ernie...

Ernie,


I'm playing devil's advocate here so bear with me!

How do you (or the IMA) justify giving aluminotschermakite an approved "full species" status when it has not been formally described?

Where is its type locality?

Where is the type specimen?


Wouldn't it be better to tag it as a (N) "named amphibole" until it is formally described? It could go in with aluminowinchite, aluminosadanagaite, alumino-ferropargasite and alumino-ferro-edenite (I know of data corresponding to all of these).


One comment for those on the amphibole subcommittee - please could you publish a computer program (ideally an excel spreadsheet) to calculate amphibole names when the nomenclature is revised. With most amphibole data collected using an electron microprobe, naming amphiboles is a nightmare - especially as Fe3+ has to be taken into account.

Andy:


I am certainly not going to defend the practice of giving species names to hypothetical minerals for which there are no known occurrences, as has been done by the Amphibole Subcommittee. Such names present a problem when it comes to assigning a status designation and, under these circumstances, I was obliged to make the least bad choice. I queried Prof. Leake, the former chairman of the Subcommittee, about such minerals, and, in the case of aluminotschermakite, he pointed me to a reference in DH&Z as representing a mineral the composition of which corresponds to the definition of aluminotschermakite. The locality given for this mineral is Warsak in northwest Pakistan, so this could, perhaps be regarded as the type locality. So this gives us a name approved by the IMA, an occurrence, and the chemical composition of a naturally occurring mineral. This information, of course, falls far short of the normal requirements for establishing a mineral species, and it is difficult to decide what the formal status of such a mineral should be. Your suggestion of "N" (not approved) is not really correct because the name WAS approved. "H" is not appropriate, either, because there is natural occurrence of the mineral. "A" is also not entirely appropriate because a detailed description is lacking. So I had to make a choice from among several unsatisfactory alternatives, and "A" seemed to be closest to the mark. Perhaps a different status designation could be invented. Any ideas?


Ernie...

Andy and others,


I passed your comments onto the current amphibole subcommittee.


Stu

Perhaps status "K" = Known occurence in nature but lacking in detailed description ?


Antonio

Isn't 'K' the same, effectively, as 'G'?


Even though it seems a little silly to be adding NEW grandfathered names, the logic behind them is the same - something believed to be a valid mineral but hasn't had a formal approval process based on a thorough analysis of type material?


Jolyon

How about 'P' for 'problematic' or 'pain in the ****'?

How about a two-lettter system to avoid confusion


AP - Approved pending further clarification and publication.

AT - Approved with a published type description

AG - Accepted due to grandfather status

AN - Approved name for an end-member not yet proven in nature


PP - Not valid, published without approval

PR - Not valid, needs further research, eg lack of type material

PO - Not valid due to anthropogenic/organic origin


NR - Not valid, rejected

ND - Not valid, discredited


etc.


We could then have a distinction between minerals that are approved and not yet published with those that are published, and the status would change from AP to AT once the description is published, so IMA2008-0xx entries would be AP status.


AN could also change to AT after further research and publication if a valid sample that satisfies tfhe 50% rule is found.


We also have an easy way of then saying if it starts with A it's a valid mineral, if it starts with P then it's probably not, but might be (depending on future research) and if it starts with N then it isn't. The distinction for P and N is important to list those things that need further research, and everythting in P should be shifted to an A or an N over time, with luck (and enough material or better test equipment in the future).


Jolyon

Also, things could be rejected as NR or PR depending on how 'final' the decision is!


Jolyon

You also have the 'named amphiboles' where a name, based on chemical analysis and crystal system, that agrees with the system of amphibole nomenclature can be published without IMA apporval. They are not considered new species of amphibole (see the article CM 42,1881) until they are submitted to the Commission and are approved.

IMA 'H' status or 'N' status.

Ernie,


"............Your suggestion of "N" (not approved) is not really correct because the name WAS approved."

I was not suggesting this - I suggested "N" to represent "named amphiboles". I was in effect suggesting lumping together the IMA approved amphibole species that do not have formal descriptions (like aluminotschermakite) together with those that are not IMA approved (the named amphiboles) - such as aluminowinchite. This would combine all those amphiboles lacking formal descriptions. All the names I listed in my previous email have published compositional data confirming their existence and so you could argue they have type localities (but not carefully curated type specimens).


Just checking - "named amphiboles" can be defined on the basis of a partial chemical analysis? Is that right? I'd guess most published amphibole data does not have supporting XRD data or analyses of Li, Fe2+ or Fe3+


I find Jolyon's two letter coding attractive. I'd give the "named amphiboles" an NM designation (named mineral). I wouldn't want them called NA as that is too restrictive. I know of two "named tourmalines" - fluor-elbaite and fluor-schorl. Both with data reported in the literature, but not IMA approved. Perhaps Jolyon would like "named minerals" designated with a P - so PN is another possible abbreviation for them.


Andy

Thanks for the suggestions. Jolyon's 2-letter coding certainly has merit, as it has the potential of removing the ambiguity in status designation that has been revealed by this exchange. As the status codings are included in the IMA Mineral List, I think that authorization for major changes, such as those suggested, should be obtained from the CNMNC. Stu, do you think that this is a project that could be taken on, possibly by the vice-chairman on classification?


Ernie

Obviously my particular example two letter codes may or may not be appropriate - they were quick five minute examples to show the concept, but I think the general concept will work well and obviously we'd support the new coding system in mindat as soon as they are announced by the IMA.


Jolyon

Hi all,

I haven't gone deeper in to this discussion but it certainly must touch upon something I brought up and discussed with (at least) Ernie more than 2 years ago:

The issue was grandfathered (G marked) minerals that had become approved (A marked) with reference to appendix table 2 in an 1987 article (Am Min 72, 1031). It concerned several mineral names affected by the Levinson rule, for example the minerals yttrotantalite and yttrocolumbite. I see in the latest IMA/CNMNC list that the problem "has been taken care of" by not giving this reference any longer. The minerals are still erroneously Approved but now using other references, e.g. Handbook of Mineralogy 1997.

The fact remains that these minerals were and are only grandfathered and their names were and are only revised, i.e. RENAMED, to yttrotantalite-(Y) and yttrocolumbite-(Y), NO scientific rework had been done on the minerals and consequently no decisions have been taken on their species status.

Yttrotantalite-(Y) and yttrocolumbite-(Y) are only given as examples. I am not reflecting on their possible validity/non-validity as minerals, but only referring to their present publicly known status. According to the present shorthand for status they ought to be marked G, Rn or equivalent - nothing else.


all best

Ok, if someone wants to run with the two-letter idea and put together a formal proposal, please consider this:


Do not choose two letter combinations that are easily inverted, eg:


AP - Approved, Published


PA - Pending Approval


because it will happen that one will get mistyped as the other.


You also might want to think about proximity of keys on keyboard and also how these things are spoken phonetically so if someone gives AS as a code over the phone it isn't mistaken for AF, or vice versa.


If you're going to think up a new system, do it right :)


Jolyon

Ernie, it is possible, but it will have to go behind the 2 major projects we aree working on now.

Hi, Johan:


You are right about yttrotantalite and yttrocolumbite. I will change their status from A to Rn (renamed), as the IMA decision was simply a renaming exercise. I will see if a similar treatment should be applied to any other minerals.


Cheers, Ernie

Reference:

• Robinson, P., Solli, A., Engvik, A., Erambert, M., Bingen, B., Schiellerup, H., Njange, F. (2008): Solid solution between potassic-obertiite and potassic-fluoro-magnesio-arfvedsonite in a silica-rich lamproite from northeastern Mozambique. European Journal of Mineralogy, 20, (in press).


I think that they are other two Named Minerals.

A new reference for sodicgedrite:


Kanazawa, T., Tsunogae, T., Sato, K. & Santosh, M. (2009): The stability and origin of sodicgedrite in ultrahigh-temperature Mg-Al granulites: a case study from the Gondwana suture in southern India. Contributions to Mineralogy and Petrology, 157, 95-110.


Abstract:

Mg-Al-rich rocks from the Palghat-Cauvery Shear Zone System (PCSZ) within the Gondwana suture zone in southern India contain sodicgedrite as one of the prograde to peak phases, stable during T = 900–990°C ultrahigh-temperature metamorphism. Gedrite in these samples is Mg-rich (Mg/ = X Mg = 0.69–0.80) and shows wide variation in Na2O content (1.4–2.3 wt.%, NaA = 0.33–0.61 pfu). Gedrite adjacent to kyanite pseudomorph is in part mantled by garnet and cordierite. The gedrite proximal to garnet shows an increase in NaA and AlIV from the core (NaA = 0.40–0.51 pfu, AlIV = 1.6–1.9 pfu) to the rim (NaA = 0.49–0.61 pfu, AlIV = 2.0–2.2 pfu), suggesting the progress of the following dehydration reaction: Ged + Ky → Na-Ged + Grt + Crd + H2O. This reaction suggests that, as the reactants broke down during the prograde stage, the remaining gedrite became enriched in Na to form sodicgedrite, which is regarded as a unique feature of high-grade rocks with Mg-Al-rich and K–Si-poor bulk chemistry. We carried out high-P-T experimental studies on natural sodicgedrite and the results indicate that gedrite and melt are stable phases at 12 kbar and 1,000°C. However, the product gedrite is Na-poor with only <0.13 wt.% Na2O (NaA = 0.015–0.034 pfu). In contrast, the matrix glass contains up to 8.5 wt.% Na2O, suggesting that, with the progressive melting of the starting material, Na was partitioned into the melt rather than gedrite. The results therefore imply that the occurrence of sodicgedrite in the UHT rocks of the PCSZ is probably due to the low H2O activity during peak P-T conditions that restricted extensive partial melting in these rocks, leaving Na partitioned into the solid phase (gedrite). The occurrence of abundant primary CO2-rich fluid inclusions in this rock, which possibly infiltrated along the collisional suture during the final amalgamation of the Gondwana supercontinent, strengthens the inference of low water activity.

Reference added.

Publication Date is 07/2008.