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Improving Mindat.orgBug entering mineral name

26th Oct 2016 13:31 UTCPascal Chollet Expert

Hi.

I found a bug trying to enter a mineral name ( http://www.mindat.org/photo-180483.html )

As it is not analysed, i whised to enter "apatite group"

- Writing "apatite" in the field, "apatite group" does not display in the select list

- Writing "apatite group" in the field, the select list displays "Epidote supergroup" ! :-S

- Same thing while writing "apatite supergroup" in the field

Pascal

26th Oct 2016 13:54 UTCDavid Von Bargen Manager

We don't allow apatite group to be added to mineral lists. If you don't know which apatite it is (Fluorapatite, Chlorapatite or hydroxylapatite), it is best to just use the generic apatite term.

The group contains mimetite and vandinite and other disparate minerals.

26th Oct 2016 15:02 UTCPascal Chollet Expert

Yes, but problem is that I can't tell if it is apatite, mimetite or pyromorphite ! (look at the photo, you will see that visual identification is quite impossible) So generic apatite term should be incorrect.

And displaying Epidote while entering apatite remains a bug.

Pascal

26th Oct 2016 15:41 UTCDavid Von Bargen Manager

OK, I manually changed it to apatite group.

28th Oct 2016 21:15 UTCRalph S Bottrill 🌟 Manager

Pascall, how can you be sure its an apatite group mineral? There are many other possibilities for minerals of this form.

28th Oct 2016 22:13 UTCPascal Chollet Expert

Well, in this locality (Les Montmins mine http://www.mindat.org/loc-1669.html ) Apatite, pyromorphite or mimetite matches the best. Don't really see what else this could be.

Pascal

29th Oct 2016 14:58 UTCUwe Kolitsch Manager

Ralph: I had analysed visually similar material. Part of it was +/- altered fluorapatite, part had overgrowths of Pb-members on fluorapatite, part seemed to be pseudomorphs. Studies of cross-sections would have been ideal, but I hadn't done that.

30th Oct 2016 20:26 UTCRalph S Bottrill 🌟 Manager

Good work Uwe, can we amend the photo description accordingly?

31st Oct 2016 18:33 UTCUwe Kolitsch Manager

I had not analysed this specific specimen, so apatite group is fine.

31st Oct 2016 20:23 UTCRalph S Bottrill 🌟 Manager

Do you think it could be grading into pyromorphite Uwe? Or fluorphosphohedyphane?

Otherwise if it resembles the fluorapatite you analysed but no other members of the apatite group or other minerals found there, isnt fluorapatite a reasonable name for it? Apatite group is very diverse and not very useful as a name for a specimen nless the chemistry is complex.

Also "apatite" is listed as a synonym of fluorapatite, chlorapatite and hydroxylapatite, not grammatically correct, it should be a subgroup really.

31st Oct 2016 20:32 UTCPascal Chollet Expert

(To Uwe's message) That's what I think too.

Such samples are always questionnables... and until it is not "personnally" analysed you can only give a group name.

I'm slowly (but surely) renaming all my beudantite, corkite, plumbogummite, kintoreite, gorceixite, etc.... with the generic "Alunite supergroup" name, until it is analysed, or very significant (e.g. blue samples can be reasonnably believed to be plumbogummite).

"Also "apatite" is listed as a synonym of fluorapatite, chlorapatite and hydroxylapatite, not grammatically correct, it should be a subgroup really"

Indeed : but does not match the (still possible) mimetite-pyromorphite series

Pascal

31st Oct 2016 20:37 UTCRalph S Bottrill 🌟 Manager

Thats the question Pascal, is there enough Pb around for it to be a Pb member of the group? Or could it be a calcite or alunite, just having a hexagonal habit doesnt make it an apatite group, without some chemical justification.

31st Oct 2016 21:20 UTCPascal Chollet Expert

Well, in this locality (this vein is a part of the 2nd tungsten occurence in France, after Salau http://www.mindat.org/loc-49408.html ) Pb members of the group are dominant ! "Apatite" is the rarest (far away).

Apatite (+ fluorapatite) : 4 pictures http://www.mindat.org/gallery.php?loc=1669&min=29229

Mimetite : 26 pictures http://www.mindat.org/gallery.php?loc=1669&min=2714

Mimetite-pyromorphite series : 44 pictures http://www.mindat.org/gallery.php?loc=1669&min=32349

Pyromorphite : 11 pictures http://www.mindat.org/gallery.php?loc=1669&min=3320

Last three should be merged as Mimetite-pyromorphite series (In my opinion, and including my own pictures)

There are more than 30 lead bearing minerals (over 122 valid species) : http://www.mindat.org/loc-1669.html and clic on Pb in "filter mineral list"

Pascal

1st Nov 2016 16:48 UTCUwe Kolitsch Manager

I added "(probably fluorapatite)" to the photo caption and referred to this thread.

1st Nov 2016 20:13 UTCRalph S Bottrill 🌟 Manager

Excellent thanks Uwe.

17th Oct 2022 14:16 UTCPascal Chollet Expert

Hi everybody

Several years later, I finally performed a SEM-EDS analyse on the sample.

Analyse was performed on full sample, without picking anything, in Low-Vac mode.

Results are (% at.)

Pb = 6.99 - Ca = 5.63

P = 12.1 - As = 0

Cl = 5.35 - F = 3.06

This matches Uwe results, althought lead seems dominant on calcium (stoechiometry is not great). On BSE mode SEM image color is uniform. this doesn't seem to be layers or heterogenous composition.

The most probable seems to be Phosphohedyphane-Fluorphosphohedyphane solid solution

Pascal

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