Levyne does not seem to be?

Hi !!
This mineral is in a cavity and attached with Dawsonite and Quartz and is from Francon quarry - Canada. It is similar to Levyne. Can anyone give me any guesses. Perhaps Tridymite ???
Thank you.

Martins da Pedra



Edited 1 time(s). Last edit at 07/01/2012 04:51PM by António Manuel Ináçio Martins.

This habit is not unusual for a carbonate.

Did you test for carbonate with acid? Calcite??

Hi!!
No, i dont teste with HCL, because the crystals field is so much litle. Is not Calcite because the Calcite from this quarry have a diferent habit.
Thanks.
Martins da Pedra

Hi Martins da Pedra, siderite is my guess...

Olá Rui
No...see the Siderite of this quarry. I have a MM with Siderite of Francon quarry and is the same habit.
To me is Tridymite or Levyne but is a guess

Thanks

Martins da Pedra



Edited 1 time(s). Last edit at 07/02/2012 01:46PM by António Manuel Ináçio Martins.

I'm not too familiar with Francon, but similar bladed xls from Varennes are microcline. See for example.

Olá Modris
Yes....maybe Microcline or Albite.....good guess...thanks.

Martins da Pedra

Olá António

I don't know about Francon - I only have a few specimens. But all of the albite that I have seen at Varennes - it is rather uncommon there - has a long bladed habit. Tabular microcline, on the other hand, lines nearly every miarolitic cavity there.

Modris

"No, i dont teste with HCL, because the crystals field is so much litle."

Just remove a tiny fragment and put it into a small drop of vinegar or dilute HCl on a glass slide.
Any reaction can be watched under the microscope - take care, however, the acid fumes can corrode the metal parts of your microscope.

Hi Antonio,

Looks similar to Dolomite-Ankerite both are listed at Francon but no images shown on the Mindat page.Bill Lechner
might be able to ID if you contact him. I still have a lot of mounted Francon specimens from another mineral collection
I acquired that were not labelled.Might check for fluorescence also, sometimes helps ID specimens.

Cliff

Looks like dolomite to me?

Spencer.

Martins,

Until you follow Uwe Kolitsch's advice and runs some simple acid tests, the vast majority of responses you get on this forum will be simply speculation, and of no real use to you. Only a minute amount of sample is required to determine if the species is a carbonate or not and this will narrow down the possibilities.

Regards,

Ben.

Hi friends!!
I think the guess more certain is to try to see if it is a carbonate through the test HCL.

Thanks .... Martins da Pedra

I took a look through my extensive collection of Francon specimens ( all 12 of them ) and noticed that I had one sample labeled as "albite, dawsonoie, quartz".

The albite looks very similar to Martins da Pedra's photo. Of course that doesn't prove that he has albite. But should the test for carbonate fail, I think that albite would be a good bet. Furthermore, since I neither collected nor labeled this specimen myself, the ID should be good

Olá Modris
I've done the test and no bubbles. I believe that is albite compared with your picture. A friend from Canada sent me several samples of Francon quarry to identify and have in hand some minerals that are not represented in Mindat.

Thanks of your atention my friend

Martins da Pedra

Hi António,

I did a bit of reading on Francon last night. There have been two articles in the Mineralogical Record (Vol 24 # 5 and Vol 37 #1).

The more recent article (by Horváth et al) states that "albite is very common as a drusy cavity lining in both the upper and lower sills. It occurs as vitreous to dull, colorless to opaque white plates up to 3 mm long. The plates consist of individual crystals stacked along [010] with sharply pointed terminations extending from the plates, producing a serrated edge." However there don't seem to be any photos with albite in this article.

The earlier article (by Fisher and Glenn) does not address albite specifically but "bladed albite" is shown as an accessory mineral in some of the drawings.

Based on that (plus your test) I would say that albite is a very safe ID for your material.

Apparently albite plays somewhat the same role at Francon that microcline does at Varennes. (I mention the latter because Francon and Varennes are both alkaline intrusions in the "Montérégian Hills".)

Regards - Modris

It's a feldspar, no doubt. Not uncommon at Francon. if you put Francon in the title, perhaps Laszlo would notice and confirm the ID.

Hi Modris and Tim !!!

Thanks again

Martins da Pedra