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Improving Mindat.orgHelp needed on Amphiboles

5th Sep 2014 00:08 UTCReynaldo Contreira Expert

Hello everybody,

As an amateur, I am completely lost in the amphibole supergroup...

Anyway in my view, there are some points to be corrected in Mindat at http://www.mindat.org/min-207.html

1. Mangano-ferri-eckermannite should be included in the Amphibole supergroup list;

2. Mangano-arfvedsonite should be excluded from the Amphibole supergroup list (renamed Mangano-ferri-eckermannite);

3. Cummingtonite (of Dewey) should be excluded from the Amphibole supergroup list;

4. Ferro-chloro-pargsite (status: Unnamed - Invalid) should be excluded from the Amphibole supergroup list;

5. Fluoro-sodic-clinoholmquistite (status: Not approved) should be excluded from the Amphibole supergroup list;

6. Sodic-ferri-clinoferroholmquistite (status: Discredited 2012) should be excluded from the Amphibole supergroup list.

Also some status revision are necessary:

7. Ferro-fluoro-leakeite (no status today) should be changed to "Hypothetical"

8. Ferro-ferri-barroisite (no status today) should be changed to "Hypothetical"

9. Ferro-ferri-fluoro-katophorite (no status today) should be changed to "Hypothetical"

Finally a question:

- Sodicgedrite and Sodic-ferrogedrite are really approved species?

Thanks

Reynaldo

5th Sep 2014 07:22 UTCOlav Revheim Manager

Thank you Reynaldo,

I'll look into your comments.

With regards to your question, neither Sodicgedrite nor Sodic-ferrogedrite are approved species according to the latest IMA species list. I'll check on their status

Olav

5th Sep 2014 09:34 UTCOlav Revheim Manager

Reynaldo,

Thank you very much for bringing these matters up for discussion. I have made the changes you suggested for your bullets

1), 2) and 3). The name mangano-ferri-eckermannite is debatable, as the name mangano-arfvedsonite corresponds to the exact same chemical formula, and may introduce uncertainty in how the amphibole nomenclature shall be applied ( think ferri-eckermannite vs arfvedsonite and also ferri-pargasite vs hastingsite). I have contacted IMA on the matter.

Ferro-chloro-pargasite (bullet 4) is as ferro-ferri-barroisite ( bullet 8) amphiboles in the category "named". This is a special IMA category for amphiboles that are published based on microprobe data alone, without any structural work. Often also the Fe³⁺/Fe²⁺ ratio is calculated. I have changed the status for these to "published without approval", which is the closest one gets. The most common "named" amphibole is fluoro-tremolite that are known for a large number of localities in the USA and Canada. I think that several of the other "named" amphiboles listed on mindat needs a status update, and also a verification that their composition corresponds with the name. If you find more of them, please let me know.

5) I do not know the history behind the name fluoro-sodic-clinoholmquistite, and do therefore not know what to do with it.

7) I have changed the status to discredited

9) Changed to hypothetical

Sodic-gedrite and sodic-ferro-gedrite, and also sodic-anthophyllite and sodic-ferro-anthophyllite are not valid names anymore. They are considered new root names ( root-name 1 and root name 2 in the 2012 amphibole nomenclature), but as far as I know, they have not been given a new name yet, and I have chosen to keep the old until a new name is in place. This is a practice that can (and should) be discussed. The same also applies to mangano-cummingtonite (root name 3).

On a general basis, both valid species, hypotethical species, "named" species are listed on the ampihbole super-group list. Also the discredited species that corresponds to a valid hypotetical species are included. I'd appreciate any suggestions and/or comments on how the amphibole supergroup hirearchy should be presented. Perhaps a column in the listing with the IMA status of each mineral would be useful?

Again, thank you for the comments, and any errors and suggestions are highly welcome.

Thanks

Olav

6th Sep 2014 22:47 UTCReynaldo Contreira Expert

Thanks Olav,

For the amphibole supergroup I would suggest to follow mindat rules:

- approved species in bold

- hypothetical/published without approval in normal font

- not approved/discredited in italics

I understand you are using bold letters to define the groups in the supergroup, but you can play with different positions in the line instead.

And I have identified few other issues:

a) Ferro-leakeite (status: Redefined approved 2012): should be "Hypothetical"?

b) Leakeite (status: Redefined approved 2012): should be "Hypothetical"?

c) Potassic-leakeite (status: Redefined approved 2012): should be "Hypothetical"?

d) Ferro-barroisite (status: Redefined approved 2012): should be "published without approval"?

e) Ferri-barroisite (status: Renamed approved 2012): should be "published without approval"?

f) Ferri-katophorite (status: Redefined approved 2012): should be "published without approval"?

g) Potassic-richterite (status Not approved): should be "Hypothetical"?

h) Potassic-ferro-richterite (status Not approved): should be "Hypothetical"?

Regards

Reynaldo

7th Sep 2014 18:11 UTCOlav Revheim Manager

Thank you Reynaldo,

I have changed a) to e) as pr. your recommendation. Ferri-katophorite is listed as an approved mineral in the July update of the IMA mineral list. I have changed the status to Approved. The two richterite minerals I have changed to published without approval.

Olav

8th Sep 2014 15:48 UTCPeter Haas

Perhaps we should ask Jolyon to add 'hypothetical' as a new category.

Changing 'hypothetical' to 'published without approval' for minerals that actually weren't published (as there is no mineral to publish - they wouldn't be hypothetical otherwise) is causing me some headache.

8th Sep 2014 16:01 UTCDavid Von Bargen Manager

"Perhaps we should ask Jolyon to add 'hypothetical' as a new category. " - you can already add a mineral in that category.

8th Sep 2014 18:12 UTCPeter Haas

Thank you, David.

8th Sep 2014 18:33 UTCOlav Revheim Manager

Peter,

In theory, all the amphiboles with IMA status as "published without approval" comply with the requirement set forth in Burke and Leake (2004): "Named amphiboles":A new category of amphiboles recognized by the International Mineralogical Association (IMA) and the proper order of prefixes to be used in amphibole names. The Canadian Mineralogist Vol. 42, pp. 1881-1883:

"The IMA–CNMMN has now recognized a new category of names, “named amphiboles”, which can be published without its previous approval, so long as the names agree with its system of amphibole nomenclature. Generally in these cases, only the chemical composition and the symmetry, either monoclinic or orthorhombic, will be known. These are not new species of amphibole, and the IMA–CNMMN criteria for recognition of new species remain unchanged".

How to use the "named amphibole" category is further defined in amphibole nomenclature by Hawthorne et al. (2012).

In reality, "named amphibole" category is a limbo status of semi-accepted names, fluoro-tremolite is the best known of them.

Olav

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