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Darryl
Joined: 12 Oct 2009
Posts: 32
Location: Amarillo, Texas
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 Posted: Aug 22, 2011 03:54 Post subject: What characteristics were used to make the determination of the localities? |
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Hello Jordi,
This is one of several comments I have read on this forum about the locality of a specimen being a particular area or mine and, having little knowledge and no experience in this area, I was wondering what characteristics were used to make the determination. I would guess there is not a single set of criteria used universally but I would find it interesting if you and/or others in the group could list and discuss a few and give some expamples. I have no doubt about the ability of the people who have made such comments to recognize minerals from a particular locality but I don't know how they do it.
The blue fluorite crystals in the post to which your comment ( https://www.mineral-forum.com/message-board/viewtopic.php?p=19093#19093 ) refers is a an example of my inability to determine a locality. When I saw them I immediately thought of an abandoned mine in New Mexico where we had collected what looked to me like similar crystals when I was a student. Obviously I was wrong but it struck me that I didn't know why I was wrong.
Thanks for any comments or information you or others may care to pass along.
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
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Location: Barcelona
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| Posted: Aug 22, 2011 04:34 Post subject: Re: What characteristics were used to make the determination of the localities? |
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Very interesting topic Darryl, I splitted your post from the former thread and I created with it a new thread. As currently I'm extremely busy I can't answer you properly right now, but I'm sure my colleagues will do it even better than me! ;-)
On case they don't, I'll answer you after a while when I have more time. It is a complex topic and I prefer don't answer you instead to do it improperly.
| Darryl wrote: |
...When I saw them I immediately thought of an abandoned mine in New Mexico where we had collected what looked to me like similar crystals when I was a student....
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Right Darryl, but on this case the starting point is that Stan Feng said: "China" ( https://www.mineral-forum.com/message-board/viewtopic.php?p=18906#18906 ) and his word is extremely valid as he his located in Singapore.... ;-)
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Antonio Alcaide
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Joined: 23 Aug 2009
Posts: 314
Location: Spain
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| Posted: Aug 23, 2011 03:19 Post subject: Re: What characteristics were used to make the determination of the localities? |
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Very interesting topic indeed!!
Trying to add one more point to this complex matter: are not some of you amazed or confused when looking at very similar specimens coming from very distant countries? I know the geological formations can be identical, but the fact still remains.
For instance, the specimens coming from skarns. It would be very tricky for me to identify two similar specimens from two different skarns. There are minerals that have specific features so it is easy to say: "doubtless it is from...". I am thinking in stepped Fluorite cubes with deep colored edges on Sphalerite from Elmwood or Prehnite balls with Epidote from Mali, Pyrites from Navajun, raspberry Grossular from Coahuila and hundreds of examples like these. On the other hand we have pairs -even more- of very similar specimens but coming from distant localities.
What about adding some pictures of these last situations in another thread?
If Jordi considers it a good idea and splits this thread -please, Jordi, do not hurry up-, I will try to start with an example from my own collection -a limited one, I am afraid-. The title could be something like: "it looks like from... but it is actually from..." or "Reasonalbe resemblances" - like the TV program-.
Regards
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Jordi Fabre
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Location: Barcelona
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| Posted: Aug 23, 2011 03:35 Post subject: Re: What characteristics were used to make the determination of the localities? |
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| Antonio Alcaide wrote: |
If Jordi considers it a good idea and splits this thread, I will try to start with an example from my own collection. The title could be something like: "it looks like from... but it is actually from..." or "Reasonalbe resemblances" - like the TV program-.
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Great idea, but I believe it would be better to continue this topic here instead to open another thread and move between both threads.
Anyway, please do it if you consider it necessary.
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Antonio Alcaide
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Posts: 314
Location: Spain
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| Posted: Aug 23, 2011 03:44 Post subject: Re: What characteristics were used to make the determination of the localities? |
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| Jordi Fabre wrote: | Great idea, but I believe it would be better to continue this topic here instead to open another thread and move between both threads.
Anyway, please do it if you consider it necessary. |
I agree with you. Better if we manage only one topic. I suppose It could be "the other side of the coin" : when identification is ambiguous due to the similarity.
Let me check my collection to provide a clear example.
Regards
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Darryl
Joined: 12 Oct 2009
Posts: 32
Location: Amarillo, Texas
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| Posted: Aug 23, 2011 10:21 Post subject: Re: What characteristics were used to make the determination of the localities? |
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Glad you fellows thought my question interesting. I am sitting on well right now but will be home in a couple of weeks and I think I can get some photos of the blue fluorite I was thinking of when I saw the other photos.
Darryl
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Antonio Alcaide
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| Posted: Aug 23, 2011 18:11 Post subject: Re: What characteristics were used to make the determination of the localities? |
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First of all, my apologies: as I said my collection is not great so I have not so many pairs of examples. I am going to complete the pairs with specimens from the large gallery of Mindat.
First picture.
It could be Hematite, var. iron rose from Switzerland. Like these:
https://www.mindat.org/gallery.php?cform_is_valid=1&loc=7103&min=1856&cf_pager_page=1
A regular collector, even a conoisseur could identify the specimen this way.
And it is actually from Xichang Mine, Xichang Co., Liangshan Autonomous Prefecture, Sichuan, China,
The clues for a correct identification: no Adularia, no Rutile... but there are specimens from Switzerland only with Quartz like the example. The best clue: it is owned by Antonio Alcaide, it is to say, by myself and specimens from Switzerland are very expensive for me :-)
I will try to add other examples.
Regards
| Description: |
Hematite var. iron rose on Quartz
Xichang Mine, Xichang Co., Liangshan Autonomous Prefecture, Sichuan, China
4 x 3,5 cm.
Iron rose measures 2,5 cm. long |
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Jordi Fabre
Overall coordinator of the Forum
Joined: 07 Aug 2006
Posts: 4897
Location: Barcelona
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| Posted: Sep 24, 2011 15:05 Post subject: Re: What characteristics were used to make the determination of the localities? |
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| Darryl wrote: |
I would guess there is not a single set of criteria used universally but I would find it interesting if you and/or others in the group could list and discuss a few and give some examples
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Hi Darryl,
I believe the keyword is "terabytes"! ;-)
Minerals are something special, each one is different from the others and although specimens of the same species from the same deposit tend to be similar, each mineral is an individual, two equals don't exist.
What does this mean? it means that to recognize the specimens you should have inside your mind a giant amount of information and also the hability to manage it well, in order to use the various subtle details of the previous info you accumulated. Museums, collections, magazines, field collecting...everything contributes, but you need vast experience because minerals present an enormous amount of information, and that information should be also very diversified about species, localities and slight differences in order to try to match the target of the correct recognition.
There is much more to say. I will wait a little bit and I will join the discussion (if it starts). If not, later, I will write again more of my thoughts about this very interesting topic.
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