FMF - Friends of Minerals Forum, discussion and message board

[BlueCapProductions]

I learned of a new mineral term - new to me at least - while I was in Tucson and was hoping that someone could help me out with the proper spelling, usage and definition.

The term is "foeted" or "foitid" - pronounced "foi-tid"

My understanding is that it's used to describe the white layer that occurs when tourmaline breaks, heals and continues growing but at a slight curve.

I've been told that this term has been in use for about 20 years and it may be a sub-species of elbaite.

Can anyone help out here? Again, I'd like to know the correct spelling, the correct usage (i.e. is it actually called "foete" and so a tourmaline piece can be said to be "foeted" if it contains the "foete") and the actual definition of what "foete" is.

Thank you in advance!!

-Bryan

[BlueCapProductions]

Here's a screen capture of what a "foete" is supposed to be.

[Pete Modreski]

Well, that's a good question; I've never heard of such a term.

What it sounds most like to me is that someone was talking about "foitite", which is indeed a relatively recently discovered species of tourmaline--which does make it related to elbaite. (You can look foitite up on mindat.org.) It's conceivable that at some particular locality, the late overgrowth of tourmaline that healed a fractured crystal, happened to be the chemical species, foitite.

Perhaps someone else knows something more that relates to this.

Pete Modreski

[alfredo]

I had been really puzzling over this term, but now I think Pete's explanation is likely correct. Such a simple explanation, I feel like an idiot for not thinking of it myself!

[lluis]

Good morning

I agree with Pete in the explanation.
But I have a doubt
-Foitite looks black to eyes, no withe/whitish

I have heard/read that the moor's caps elbaites in Elba, the black part is foitite. So, elbaite and foitite come along.

But for white, I could only think in magnesiofoitite...
That could be right?

The veils I see a just a rehealed fracture, no different material (unless a XRF is done of that zone and shows opposite...)

With best wishes

Lluís

[Peter]

Hi Bryan

As Peter M is writing Foitite is a specie in the tourmaline group. In January 1993 I was in a pegmatite the Kazennitsa Mine, in Alabashka, n of Murzinka in the Urals. In a pocket at 27-28 m depth I saw a very thin fracture behind the pocket walls coated by large albite balls, smojy quartz etc. This thin fissure was thus created by pocket eruption and on its walls f=grow thin flattened late stage quartz crystals, and more interesting in the 1-2 cm wide clay filling I saw minute ends of mm thin tourmaline needles. In May 1993 I took these to analyse as they were extremely late stage and could be of interesting composition. We did not establish a vacant x-site, which is the special with this tourmaline. Thus probably the brightest mineralogist of our days, Professor Frank Hawthorne was analysing a (I think it was two crystals) of tourmaline from "California" and I think in November 93 etsablished the new specie Foitite,

Now, what is interesting is the fact that the vacant site seem to only occur frequantly enough in very late stage tourmaline, thus growing on the end of crystals, probably also as i this case filling late stage breake and reheal. I did not see analyses of this last.

Another specie is Rossmanite is another alkali deficient tourmaline described in 1998, and found and suspected in 1995 due to its occurence also in extremely late stage mineralizations in pockets.

Bryan, let me know who was speaking of foitite in the Himalaya Mine or SD County tourmalines

[jacquestouret]

Hi, I never heard about this name (foete) for a tourmaline, even if I might suspect some Afrikaans (or Dutch) connotation (foot, meaning the end of the crystal). Anyway, I believe that I see rather clearly what it is about: a healed fracture, cutting the top of the crystal, then healed while the crystal growth did proceed. This resembles to "truncated crystals" (cristaux tronqués), it happens that I have just written a small paper on these crystals (in French, sorry!) in the coming issue (April 2009) of "Minéraux et Fossiles" magazine. These sudden stops in the crystallization are often caused by a platy mineral (most typically calcite for quartz) on the head of the growing crystal, eventually when it meets an obstacle (other crystal or wall of the fracture). The growth resumes upon further opening of the cavity. In this case, I would strongly suspect this mineral to be albite (cleavelandite), not only because of the whitish layer (beware: can be solely due to fluid inclusions), but also because I see (or at least I suspect) a distinct change in color on the upper side of the "foete" (more pinkish). Tourmaline becomes pink when it crystallizes simultaneously with albite, the iron in the solutions entering preferentially the feldspar structure. If no feldspar is present, the iron has no other alternative but entering the tourmaline structure, making the color green. If you have any doubt, come and visit us at the Ecole des Mines, Paris, you will see the demonstration.

[BlueCapProductions]

Thank all of you for your thoughts and insights.

Pete, I think you hit the nail on the head. Checking out the entry on MinDat, it does mention that foitite occurs in CA and, as Peter deduced, the piece in the photo is from the Himalaya Mine.

The gentleman who brought this to me attention was a German collector name Klaus Neuman. He has an extensive private tourmaline collection and always brings some very nice pieces to Tucson.

I've sent him an email inviting him to join this forum and contribute his knowledge on this mineral. When he talked about it to David Wilber during the filming of WHIT:09, Wilber was completely unfamiliar with the term/species. So if Wilber didn't know what it was, I felt I was in good company with my own ignorance.

According to what Klaus told us, there was some woman who gave a presentation on this during one of the Texas club meetings (don't remember if he said HAM or MAD).

Hopefully Klaus will add his comments and we can all get to the bottom of it.

BTW, assuming for the moment that it is foitite, is it proper terminology to call a tourmaline piece containing foitite (like the one in the photo) "foited" - or however one might spell it??

[Peter]

Barbara Dutrow has done a lot of research on the tourmaline group minerals and I am quite sure she is the one Klaus refers to.

[lluis]

Hi, Bryan

I agree with Pete that likely the name is for foitite.

But then I have a *big* trouble: foitite is *black*

The veils are whitish.
So, no foitite.

By the way, I have some Pala tourmalines, and I have always assumed the veils as rehealing giving a non continuous medium that leads to that opaque aspect....

I have also foitite.

With best wishes

Lluís

[Peter]

Long slender Foitite from the Kazionnitsa Mine, Urals are dark root beer colored (looking black) in incandescent light and purplish in day light! Short prismatic with foitite composition in the ends are brown.
I saw in Tucson this year, what may be foitite, very fibreous tourmaline of almost white-tan color.

[Jordi Fabre]

Bryan wrote:
>BTW, assuming for the moment that it is foitite, is it proper terminology to call a tourmaline piece containing foitite (like the one in the photo) "foited" - or however one might spell it??

I don't think that "foited" be correct. If it is Foitite (I don't believe it) the proper terminology would be Elbaite and Foitite or Elbaite with Foitite.

Hopefully this helps

Jordi

[BlueCapProductions]

OK. I just got an update from Klaus who has read this discussion but not commented directly.

So Klaus was hanging outside the Westward Look Show talking with a friend of his about tourmaline.

Barbara Dutrow, who was the woman who gave the talk to the MAD group, came by and gave Klaus the information that the re-healed colorless tourmaline should be foitite when he showed her this piece. BTW, the misspelling of "foitite" was an error of translation.

After reading this discussion and looking at the chemical formula of foitite, even Klaus now has his doubts about this really being foitite.

So was Barbara mistaken? And what about the white-tan fibreous tourmaline that Peter saw in Tucson?

Perhaps there are white foitites but they are just not that well documented. Can anyone get in touch with Barbara to see if she can clarify?

At this point it's a purely academic discussion as the whole foitite section will most likely be cut from the WHIT:09 video.

Thanks again!!!

[John S. White]

I can't resist getting into this discussion, but not to contribute anything to the original question which I believe Pete Modreski handled perfectly. I am sensitive to the term "reheal" or "rehealed" because I used it recently in something I wrote that was published in Rocks & Minerals. A reader wrote that I should have used the term "healed" rather than "rehealed" because there is no evidence that it had been broken twice, which is what "rehealed" implies. "Rehealed" suggests that a break was healed, then rebroken, and healed again. Not important, just fun with words.

[alfredo]

We can always count on John to set us straight when we misuse terminology. (I'm not being sarcastic here; I really do appreciate it!) John has been accused in the past of being too pedantic, but every group needs at least one person like him, or else languages have a tendency to degenerate to an anarchic state where words have no clearly defined meaning anymore. (Just think, for example, how the words "flammable" and "inflammable" came to mean the same thing in english!)

As for the supposed white band of "foitite"... I have no idea whether it could be foitite or not, although I agree with those who say that foitite is more likely to be dark coloured. But one other point to keep in mind is that no tourmaline is a pure end-member species; all are solid solutions of several species, named after the most abundant component. So, just to make up hypothetical (and perhaps rather unlikely) numbers here, a tourmaline whose components are 30% foitite, 28% rossmanite, 25% dravite, and 17% elbaite, could be expected to be rather pale coloured, but would officially still be a "foitite"!