FMF - Friends of Minerals Forum, discussion and message board

[Gail]

Tracy, good to hear from you! I can't wait to hear your Smithsonian Mineral stories.
What fabulous photos of your specimens, I see you can add a lot to each posting too.
Hope you are keeping well and glad to see you are posting again. Good work!

[Gail]

Tracy, you still alive girl???? Can we see more of your minerals please???

[Tracy]

Hi Gail -

Still alive but drowning in more work than one human being can handle. Will try to get some new photos up soon, I have other cool specimens to share.

Happy weekend!
Tracy

[Tracy]

One specimen to share tonight: a recently acquired schorl crystal with lots of needle-like projections at one end. It reminds me of a black comb. The cool thing is that, though it looks black under regular lighting, under a bright light (in the case of the photo below, the flash from my camera), the needles are purple. I confess I know very little about tourmalines and how they form, and I don't know whether this a second growth stage of elbaite-like "needle" crystals, or whether the entire crystal is schorl-elbaite? Alternatively, were the needles formed by etching processes? Regardless I think it's neat, but if anyone can help me understand how it came to be I'd be grateful...photos below

From Corcunda Mine, Governador Valadares, Brazil. 8 x 2.5 x 2 cm. Ex. Robert C. Lambert collection.

Lining up another batch that I will post when time permits.

- Tracy

[Jordi Fabre]

I can't be sure, but for me the specimen comes from Golconda mine (Governador Valadares, Minas Gerais) or from Serra Corcunda area (Alagoas, Brazil) but not from Corcunda Mine, that, as far as I know, it don't exist.

Nice specimen!

Jordi

[Les Presmyk]

A very interesting schorl crystal. The hairs are due to accelerated crystal growth along one axis. I know that John White or Peter Modreski can explain it much more eloquently and scientifically but envision a cubic cuprite crystal that is able to form a long needle-like crystal in the chalcotrichite form. We see wulfenite crystals due the same thing as your schorl. As far as I know, it is all schorl.

[MaryFender]

I have one of these I acquired from Frank and Wendy Melancon. We call it the "Don King" tourmaline after the boxing promoter with the hairdo. Mine is labeled Corcunda Mine, Gouvenador Valadares, MG, Brazil.

[Carles Curto]

Some of these "haired" terminations on Minas Gerais Schorl are Foitite.

[Tracy]

Carles - Making sure I understand correctly, might this be foitite growing on schorl? According to mindat, there are no localities for foitite in South America., but the description and the photos are consistent with foitite.

Mary - I still encision a black comet (probably because of the way it's mounted on the base) but I can see why you'd name yours after Don King. Good one!

Jordi - Mary's label matches with mine (I spelled Valadares wrong in my posting). If you say that the locality is incorrect, we have a bit of a mystery... ?

- Tracy

[Jordi Fabre]

Tracy,

I said that I can't be sure about this. I never hear about a mine named Corcunda in Brazil, nor after a search in different well documented sites, but Frank Melanson is a reliable source, so it could be. If I have the chance to speak with him in Tucson I will ask it to him.

Jordi

[Carles Curto]

I read about the foitite acicular or fibrous terminations from Minas Gerais. I also remember a picture in B&W, it could be from Mineralogical Record old issues, but I'm not shure.

By other, ExtraLapis English num, 3 (Tourmaline) cites Foitite iin Cruzeiro mine, Minas Gerais.

[John S. White]

It is Governador. It is Frank Melanson. Who's to say that foitte cannot occur in Brazil? It is possible, I suppose, that you could get foitite on schorl, but it is more likely that the entire crystal is more or less the same composition, very thin fragments of the black base would probably also transmit light and appear purple, just like the thin needles on the termination. It is also possible that the thin needles are the product of etching and not primary growth.

Luiz Menezes would be the person to ask about the species and the locality.

[MaryFender]

Sary fo de misspel. Just attended a lecture by Barb Dutrow and what I took away was where there is one tourmaline there are probably others. Just depends on the sampling. So I agree there is no reason not to think there is foitite in Brazil.

[parfaitelumiere]

Hello Tracy.
About your Fluorite from Teller,I think the hole came from lack of Amazonite.
I have one specimen,and there is amazonite crystals stuck on the fluorite,and the contact between amazonite and fluorite shows like the fluorite has grown on the amazonite,and there are places where amazonite has dissapeard.
The fluorite has a greenish-purple color,and a stange etched surface,not as yours.
It make me think about some specimens from Spain.

[parfaitelumiere]

on the last view it seems to be sawn(difficult to see on a photo!)but it is complete,like it had grown on a bigger amazonite crystal,that makes me think of what you described of your specimen.