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Blue Mystery Mineral

Posted by Levi Cain  
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Levi Cain July 12, 2018 09:17AM
Unfortunately I do not know local. This specimen was found covered in a thick layer of dust on the top shelf of a family operated rock shop in Oklahoma (USA). Passed down from the grandfather who passed away some years ago. So no information was known on the piece. However he dealt with minerals from all over the world. With a heavy focus on minerals from the America's and Africa.

I have suspected Euclase from Africa but my fiancee is convinced it is Blue Tourmaline. When trying to figure out how to distinguish between the two minerals, I couldn't come up with anything. I believe their is Pegmatite in the specimen along with mica/muscovite. An additional feature worth noting is that in a few areas there are small spots of an additional black mineral that only seem to occur along the edges of the blue mineral.

Sorry for the limited information and thank you for any helpful information.



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Levi Cain July 12, 2018 09:21AM
Additional photos were taken in direct sunlight. The initial pictures were taken in artificial lighting.




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Levi Cain July 12, 2018 09:26AM
Taken in artificial lighting. This shows more of the exterior pattern of the blue mineral.


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Louis Zulli July 12, 2018 11:11AM
Aquamarine beryl?

Edit---The " small spots of an additional black mineral" might be tourmaline (schorl).



Edited 1 time(s). Last edit at 07/12/2018 01:37PM by Louis Zulli.
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Wayne Corwin July 12, 2018 12:09PM
My first thought was either beryl or apatite, does it scratch with a pin ?
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Pavel Kartashov July 12, 2018 02:50PM
Manganoapatite or blue tourmaline. Definitely not beryl.
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Matt Courville July 12, 2018 03:17PM
Hi Levi, I looked very closely at the photos and the first photo almost seemed to have the cleavage of apatite, but then the last one seems to have striations leading one think to tourmaline or euclase. With such limited info and mostly rough material, you can only hope for guesses unless someone reading knows 'that' exact locality and chimes-in.

Why not try sending Kerry Day at Kaygeedee minerals a small grain-sized piece for something like $10 and find-out for fun? At his cost, it's basically for his own interest and amusement to run these for fellow collectors ;)
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Levi Cain July 12, 2018 03:26PM
When I tried to scratch it with a pen all it did was leave black ink on it.
Im joking, it did not scratch with a pen. I attempted in various spots and couldn't notice any surface scratching.

Thanks so far for the comments, I greatly appreciate any help.
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Levi Cain July 12, 2018 03:32PM
Thanks Matt Courville. That is not bad pricing at all. I might actually try that.
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Carl (Bob) Carnein July 12, 2018 04:37PM
Looks to me like blue tourmaline with quartz and albite.
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Wayne Corwin July 13, 2018 12:11AM
Levi

do you have a blacklight?
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Doug Daniels July 13, 2018 01:13AM
I would think that blue (especially THAT blue) tourmaline, of that size, is quite rare. As well as the fact the original owner specialized in the Americas and Africa; if the Americas, Brazil would be the best bet, but most of the larger bright blue tourmalines from there are fairly recent (as I remember). The end-on section in the second photo also doesn't suggest tourmaline, but maybe apatite or beryl. Trying to scratch something with a pen is kinda useless - especially if it's a ball point pen. The ball will just roll over the specimen, and not scratch it. A cheap analysis as suggested might be in order here.
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Russ Rizzo July 13, 2018 01:24AM
I'm with Levi. Given the African connection. I'll bet that it turns out to be Euclase.
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Ian Nicastro July 13, 2018 03:38AM
I strongly argue against this being Euclase. Deeply blue Euclase is rather rare and most specimens on the market are from Zimbabwe. Euclase crystals from there tend to be short, not long elongated prisms, and they tend to have dramatic localized color zoning.

This looks like Apatite or Elbaite Tourmaline. As the mineral was not scratched with steel (I would have used a nail instead of a pin)... that suggests Elbaite to me. There are multiple places in Africa that produce blue Tourmaline. I see visible striations in some of the photos that also suggest Tourmaline to me.
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Russ Rizzo July 13, 2018 06:10AM
Ian Nicastro Wrote:
-------------------------------------------------------
..... Deeply blue Euclase is rather rare and most specimens on the market are from Zimbabwe.

Exactly my point.

Levi stated that the previous owner had material from Africa. There's a really good chance that the specimen is African (Zimbabwe). He stated that this was "old" material. 50+ years ago Euclase from Africa was more common and of good, blue color. None of the photos show any euhedral crystals; just sections of a sort of gemmy, deep-blue colored mineral. The mineral was not scratched by steel. Euclase has a hardness of 7½.

Based on these facts one cannot rule out Euclase.
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Keith Compton July 13, 2018 08:30AM
My first thought was Kyanite
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Kevin Hean July 13, 2018 08:38AM
Hi Levi
Some Tourmalines have a "closed" C axis, that is, they appear black looking down the C axis .
I know this sounds like "Hokus Pokus" and I don't want all the Gem people to jump on me,
but give the crystal a rub with a piece of flannel , Tourmaline can be quite static, and will readily attract
little pieces of paper and ash, I have never tried this on tourmaline that is in matrix .
These are by no means accepted test methods but can be indicators .
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Harold Moritz July 13, 2018 12:15PM
Blue tourmaline, with typical darker cores and crude matrix crystals. I was just looking at some similar stuff from a place in Connecticut yesterday. Note the platy albite at the bottom of the second photo, typical of a complex pegmatite.
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Vincent Rigatti July 13, 2018 02:02PM
If tourmaline, the bright blue coloration is unusual but similar to Paraiba blue tourmaline from Brazil. Paraiba tourmaline also tends to be highly etched and fragmented like this specimen.
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Levi Cain July 13, 2018 05:30PM
Thanks everyone,

- Wayne, I've attached a couple pics of my cheap low quality SW blacklight results. The actual blue mineral did not seem to show any fluorescence. However, some of the surrounding minerals did. Some blotches of yellow and the more whitish colored mineral was pinkish.

- I used a steel tacking pin that was thicker then usual when I attempted to scratch the blue mineral the first time, with no noticeable results. But just now attempted the scratch test with an actual nail. When attempting to leave a scratch on a flatter plane of the blue mineral. I did not notice any scratches. However, when I attempted along the edge or along the uneven/broken surfaces of the blue mineral. I did notice very slight chipping.

- Kevin, that is very fascinating about the flannel and tourmaline being static. I am going to experiment more with that and tourmalines for personal interest in the future. However my quick testing of the specimen did not show any reaction with some dust I found on a nearby dresser.

- Harold, thanks for the info regarding Connecticut. I'm going to do some picture searching and see what all I can find regarding blue tourmaline from there.



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Harold Moritz July 13, 2018 05:41PM
Fluorescence in tourmalines like these is rare, the yellow spots are fluorapatite and the pink is albite, very typical of pegmatitic pieces.
You wont find many pix of blue tourmaline from Connecticut because that color is rare there. The material I am looking at has not been documented yet, although it was collected decades ago by a fellow who has passed on and he was the only one to collect that area and the amount is pretty meager. So your material is almost certainly not from Conn. Most likely Brazil.
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Dean Allum July 14, 2018 03:42AM
Levi,
While this exactly resembles my Fluorapitite from the Harding Mine in color and texture, mine glows distinctive yellow under SW UV.

Maybe your light is actually LW UV?

-Dean
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Levi Cain July 14, 2018 10:07AM
Thanks Harold and Dean.
Dean I found your pictures listed under the Harding Mine. I do see the resemblance, thanks for sharing those pics.
I think I'm going to see about having this specimen tested as mentioned above. LOL my fiancee keeps telling me she told me so the more I show her the comments. I'll admit I was wrong . . . at least this time that is.
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Matt Courville July 14, 2018 09:59PM
Levi, make a friendly bet with your financee and perhaps donate who wins to mindat??(whomever gets bragging rights) You will get addicted once you try sending -in samples for analysis;) Let us know the result if you do get it analyzed
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Harold Moritz July 14, 2018 10:04PM
Blue fluorapatite can certainly happen, but I would expect it to fluoresce in pegmatite, which is relatively Mn rich. Fluorapatite of that color I have seen it mostly in marbles, which are Mn poor and so it does not fluoresce. Your piece is clearly a peg though. Pegmatitic fluorapatite will commonly fluoresce yellow under LW, but albite wont really, so if you are seeing weak pink from albite, then the lamp is almost certainly SW.
Both blue elbaite and blue fluorapatite are fairly rare and when you are dealing with not well-formed crystals, IDs are more difficult. Apatite comes from the Greek apatan - "to deceive", and it does it well.
Well, always to keep an open mind about mineral IDs and collect data. It took me decades to identify some minerals, especially when both the species and the locality are unknown (the latter always the worst data to not have - but even when you have a label sometimes one or both are wrong!). But once you have the right data, you'll get the "well, duh!" moment.
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Reiner Mielke July 15, 2018 03:48PM
A hardness test will easily distinguish apatite from tourmaline.
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