Boleite from Chile

Has anyone analyzed the blue mineral that is found with the Penfieldite from the Margarita Mine in Chile? Looking at it closely I cannot see anything that is clearly cubic rather crystals that are clearly not cubic. I am inclined to call it diaboleite.



Edited 1 time(s). Last edit at 01/05/2010 12:28AM by Reiner Mielke.

How about Caladonite?

Rock Currier
Crystals not pistols.

Or Pseudoboleite?

They look like stacked or hemimorphic tetragonal plates. That can be consistent with both Diaboleite and Pseudoboleite.

Lefteris.

First photo, upper right, looks like it might be a cube.

I agree with Don.

Hello Rob and Don,

Are you suggesting that there might be more than one species of blue mineral present? That thought has occurred to me because there are some crystals that look somewhat cubic and others clearly not. However, pseudocubic seems to be a common theme among crystals and I can't see any difference in colour or luster between them. Will have to do a few tests and get back to you. The reason I even thought it might be boleite is because it was sold to me as being such and all the specimens pictured on the net say penfieldite with boleite.

John Dagenais who has a couple of these thinks it is boleite and has emailed Maurizio Dini who apparently knows about these for some clarification. My first take on these was that they didn't look very cubic, but I did notice the xl that Don pointed out. So I think the jury is still out.

XRD needed. Morphologies of these blue Pb-Cu-halogenides can be quite deceptive.

from RRUFF

[rruff.info]

this looks like our stuff from the same locality... but it's not over yet... Reiner is conducting some tests in assorted acids

Maggie

Ruff has a sample similiar to mine from that mine and it was determined that the blue mineral was Pseudoboleite. However when I placed a piece in concentrated HCl it was rapidly attacked and turned completely white in less than one minute. According to Sinkankas it is soluble in Nitric but no mention of HCl, usually that means that it is not soluble in HCl. Can anyone confirm that it is soluble in HCl.

I understand that What’s New in Minerals in Mineralogical Record, volume 33, no. 1 has information on the boleite from this locality, however, I do not have access to this January 2002 copy.

Thanks to John Betts for the assist

Maggie

A white film left after attack by cold HCl is often seen with secondary lead minerals (as well as silver-bearing minerals), so that could fit both boleite and pseudoboleite.

It was not just a white film but a total replacement by a white alteration product.

Reiner: I've always known this mineral as pseudoboleite. Rock Currier is wrong on caledonite. The caledonite/leadhillite/linarite minerals have never been found in the Margarita Mine or the Sierra Gorda area,like you have them at Tiger,Az. or Leadhills,Scotland. The Margarita Mine has the rare lead+copper oxychloride group of minerals: penfieldite,seeligerite,the boleites. It has to do with the stability curves of these groups of minerals and the enclosed environments they form in.. Besides,there are no secondary carbonate minerals at Sierra Gorda. Sulphates,yes.
When I was in the Margarita a few years back I had a chilean miner with me and we mined/ collected all this material from the lowest level. It was an abandonded mine and nasty and dangerous.Penfieldite was formerly a very rare mineral until we mined the current material on the market. I was totally surprised to find that massive+junky looking penfieldite was so common in the walls of the worked stopes in the mine it was probably an ore.(The mine was a rich lead-silver mine.) Of course,nobody collected xlized. specimens of penfieldite years ago: it all went to the crusher. Not until I came along 6-7 years ago,did the xlized. penfield come to the mineral market.
I found quite a bit of this blue mineral associated with the penfieldite,and sold it as 'pseudoboleite.' It could be diaboleite,fits the paragenesis. This penfieldite was a total unexpected surprise to me when we started working on the Sierra Gorda area. The same,a total unexpected surprise when I collected+discovered the 2 new minerals cristelite and gordaite that we collected on the dumps of the abandoned San Francisco mine 1/2 mile west of the Margarita.There I know we got all the cristelite/gordaite that was available: we dug+screened 30 metric tons of dump for these minerals. We cleaned it out. We found none of it examining the mine underground.
I have had much problems over the years having these chilean minerals identified professionally by x-ray or edx. Who can you call on to do this work now? I couldn't just run up to Harvard with every unknown to present to Dr. Carl Francis. I was so happy to have Tony Nicasher/Excalibur Mineral Co. do edx fro me in years past,but he doesn't do edx anymore. Besides,on the boleite/pseudoboleite/diaboleite group edx can't differentiate. Good luck on this one, Regards, Terry Szenics.

So as Uwe suggeast an XRD seems appropriate

Thank you very much Terry, must have been an exciting experience!
From what you have said it seems to come down to diaboleite or pseudoboleite ( boleite is out of the question, clearly not isometric). Ruff has already determined the presence of pseudoboleite in the sample of penfieldite that they looked at. I just need to confirm my test results with HCl and I will be happy to call my sample pseudoboleite as well.
I have a sample of Mexican boleite coming my way in the mail, it will be interesting to see how it reacts to HCl. Assuming pseudoboleite reacts the same way as boleite ( Sinkankas seems to think so) this simple test may help distinguish pseudoboleite from diaboleite. Wish I had a confirmed grain of pseudoboleite to play with.
Yes I know XRD would be the best way to go but I don't have access to one and it is expensive and the turnaround is long, if there is a simple and cheap way to do it I'm all for it.

Let's hope the pseudoboleite you are getting is in fact thatX(

It is sad that the almost universal use of PXRD and EDS has discouraged the kind of testing you are trying. Much can be done with a simple blowpipe kit, but now they are regarded as antiques and sold like miner's candle holders. A straw or the fronts off ball point pens, whittled bit of charcoal, an alcohol lamp and a few reagents is all one needs. Many of the newer invisible species require WDS and single xl XRD and these older metods are completely defeated. But then does a mineral collector really need to know that much detail?:S

When I was an undergrad in 1972, blowpiping and bead testing were already a lost art. My prof. asked me to demonstrate it to the mineralogy class because I was the only one he knew of who knew how to do it.

Finally got a sample of Boleite from Mexico and tested it with concentrated HCl ( didn't have a confirmed sample of Pseudoleite to test so I used Boleite). It turned totally white and colored the acid yellow. This fact is absent in Sinkankas's Data Book so note this in your books folks. I am assuming then that Pseudoboleite ( being very similiar to Boleite) will react the same way, although again Sinkankas says nothing about Pseudoboleite reacting with HCl. As such, since my unknown also turned white and Ruff's sample was pseudoboleite I am concluding that my sample is also pseudoboleite.

Almost all secondary Pb-mineral turn white on reaction with HCl - white lead chloride, PbCl2, is formed.