Log InRegister
Quick Links : The Mindat ManualThe Rock H. Currier Digital LibraryMindat Newsletter [Free Download]
Home PageAbout MindatThe Mindat ManualHistory of MindatCopyright StatusWho We AreContact UsAdvertise on Mindat
Donate to MindatCorporate SponsorshipSponsor a PageSponsored PagesMindat AdvertisersAdvertise on Mindat
Learning CenterWhat is a mineral?The most common minerals on earthInformation for EducatorsMindat ArticlesThe ElementsThe Rock H. Currier Digital LibraryGeologic Time
Minerals by PropertiesMinerals by ChemistryAdvanced Locality SearchRandom MineralRandom LocalitySearch by minIDLocalities Near MeSearch ArticlesSearch GlossaryMore Search Options
Search For:
Mineral Name:
Locality Name:
Keyword(s):
 
The Mindat ManualAdd a New PhotoRate PhotosLocality Edit ReportCoordinate Completion ReportAdd Glossary Item
Mining CompaniesStatisticsUsersMineral MuseumsClubs & OrganizationsMineral Shows & EventsThe Mindat DirectoryDevice SettingsThe Mineral Quiz
Photo SearchPhoto GalleriesSearch by ColorNew Photos TodayNew Photos YesterdayMembers' Photo GalleriesPast Photo of the Day GalleryPhotography

Identity HelpID Help - Lake Asbestos mine (Quebec, CANADA)

10th Jan 2020 18:42 UTCPierre-Luc Croteau

05007490016021064749096.jpg
I found many white and grey fibrous (like hair), in a vein associated with quartz and albite at Lake Asbestos mine near Black Lake, Quebec. I can't verify the hardness nor the density. The fibers are silky and flexible, sometimes snowy white and sometime more white-grey (as the photo shown). I had first guessed for Tremolite (which is not listed there) or Actinolite, but the fibers fuses easily under a little blowtorch and result of dark red (almost black) magnetic little balls. Nothing fluorescent.

Can you help me with this one or maybe a hint? Thank you in advance!

10th Jan 2020 19:11 UTCFrank K. Mazdab 🌟 Manager

possibly also anthophyllite, which according to Pough (this book has been especially useful this week), "fuses with some difficulty to a black magnetic glass"? More Fe-rich compositions should fuse more readily, but this is also true for fusibility within the tremolite-actinolite series. In any case, a somewhat more Fe-enriched member of one of the asbestiform amphibole series (anthophyllite-[ferro-anthophyllite] or tremolite-actinolite-[ferro-actinolite]) seems pretty plausible here, and also seems consistent with the locality's overall mineralogy. If you have access to a petrographic microscope, you might be able to differentiate usually parallel extinction ortho-amphibole from usually inclined extinction clino-amphibole, although when the minerals are in the form of very fine fibers, it can be tougher to make that distinction.

10th Jan 2020 21:01 UTCPierre-Luc Croteau

Oh thank you very much for the informations. I unfortunately don't have access to a prtrographic microscope. Anthophyllite is now my thinking too after some reading. If the fibers fuses easily and the "black magnetic glass" is very very magnetic, should it be Ferro-Anthophyllite?

10th Jan 2020 21:27 UTCFrank K. Mazdab 🌟 Manager

even if suspected of being a member of the [anthophyllite]-[ferro-anthophyllite] series, while a greater ease of fusibility (and the strongly magnetic glass product) would suggest some quite significant Fe content, unfortunately I'd say the test is at best qualitative, and so ultimately on what side of the composition boundary the sample may be is probably not unequivocally determinable without additional tests.  Additionally, incorporation of Na (so moving towards sodic-anthophyllite) and Al (moving towards gedrite and ferro-gedrite) may also be possible, as I'm not familiar with the fusibility behavior of those related species (and the gedrite series amphiboles can also occur in asbestiform habit).

10th Jan 2020 21:39 UTCPierre-Luc Croteau

From what I see on Mindat, Gedrite and Ferro-Gedrite are almost black/green. But thanks for your comments, it help me a lot! Do you know if there is an other test I can simply do at home to try to precise the identification?

11th Jan 2020 00:24 UTCFrank K. Mazdab 🌟 Manager

Unfortunately, with a few exceptions, differentiating among the various amphiboles typically requires a decent chemical chemical analysis, and in some cases perhaps even accompanied by optical, XRD and/or Mössbauer data. Offhand I can't think of any simple at-home test to differentiate among the members of amphibole series we've discussed in this thread.

11th Jan 2020 02:31 UTCPierre-Luc Croteau

So, what I write on the label!? Is there a « global » or « family » name that I can write, a kind of rule for that?

Thanks a lot Frank!

11th Jan 2020 04:34 UTCFrank K. Mazdab 🌟 Manager

well, most inclusive would simply be "amphibole" or "asbestiform amphibole".  I know it's a bit unsatisfactory, but it is likely the best choice (barring the slight possibility that the fibers might not even be an amphibole, but I suspect you're likely OK with that assumption).

"Mg-Fe-orthoamphibole" would include the entire [anthophyllite]-[ferro-anthophyllite] and [gedrite]-[ferro-gedrite] series, but would exclude the possibility of the [tremolite]-[ferro-actinolite] series (these would be "Ca-clinoamphibole", although the "clino" could be considered redundant because there are no calcic orthoamphiboles). "Asbestiform" could be added as a descriptive modifier, which would inform viewers of your specimen that from among all the amphibole species, yours is presumably one of the roughly half-dozen or so known species that has been reported in an asbestiform habit (there are a few others not included in the preceding discussion).

This "what particular species of a complex solid solution is my sample?" issue isn't unique to your specimen, of course. Even just anyone who has common "hornblende" in their mineral collection is faced with a similar dilemma, since "hornblende" is no longer a mineral and the collection of species considered under the "hornblende" umbrella could be any of (or even zoned multiple) compositions representing perhaps a couple dozen species.

In lieu of sending your specimen out to a commercial lab for analysis ($$) or taking it to your local university or museum for analysis (also possible, depending on their willingness to engage in public outreach on such matters), it's also possible collectors from a local club may be able to offer a more definitive ID, based perhaps on their own independently analyzed specimens of essentially identical material (presumably somebody was curious enough to do so). Another possibility is just reviewing the scientific literature on the deposit... it may turn out from the reports that the tremolite/actinolite from there is commonly asbestiform but the anthophyllite never is (or vice versa?).  Some of these reports may also contain analytical data, descriptions of assemblages (maybe one species is only found with quartz there while the other is only found with calcite there?), and photos of specimens... all potentially helpful tidbits of information.

11th Jan 2020 17:14 UTCPierre-Luc Croteau

Wow! What an answer!! I cannot ask for more. I want to thank you very very much! It proof that Mindat and their contributor are a powerful tool for amateur mineralogist!!

Thank you again (sorry, i’m Canadian and so too much grateful!)

11th Jan 2020 19:09 UTCFrank K. Mazdab 🌟 Manager

pas de problème, Pierre-Luc... c'était mon plaisir...

13th Jan 2020 20:05 UTCPierre-Luc Croteau

Merci :)

8th May 2020 15:14 UTCPierre-Luc Croteau

Hello again, Frank!

After some research on Mindat, do you think I can call it "Byssolite" ?

But Byssolite is not listed there on Mindat...

If the fibers fuses easily and result of magnetic little balls, is it mean that it should include "Fe" in the formula?  (the fibers themselves are not magnetic without fusing it)

Thank you in advance!

8th May 2020 22:13 UTCFrank K. Mazdab 🌟 Manager

Hi again Pierre-Luc,

I suppose your specimen would qualify as "byssolite" and you can add that name to the locality if you'd like (and if your membership level doesn't give you the ability to add minerals to a locality, let me know and I or someone else with the ability can add "byssolite" for you).

But as others here sometimes make a bit of light-hearted fun with me about, I'm not a big fan of varietal names for minerals and tend to prefer to see the names of species and series and such. But this case might be an exception, because while "byssolite" tends to be thought of as typically being part of the tremolite-actinolite series, the name may encompass other pale-colored furry amphiboles as well. And since there was some question earlier as to which particular series your furry amphibole may actually belong to, "byssolite" may indeed be the best choice to cover that ambiguity.

19th May 2020 19:48 UTCPierre-Luc Croteau

Many thanks again!

Are you able to answer my other question, i'm curious: 
If the fibers fuses easily and result of magnetic little balls, is it mean that it should include "Fe" in the formula? (the fibers themselves are not magnetic without fusing it)


19th May 2020 20:12 UTCFrank K. Mazdab 🌟 Manager

Pierre-Luc Croteau  ✉️

If the fibers fuses easily and result of magnetic little balls, is it mean that it should include "Fe" in the formula? (the fibers themselves are not magnetic without fusing it)

 yes, that is correct, but I don't know at what minimum Fe concentration along the Mg-dominant to Fe-dominant join that observation begins to hold true, so I don't know if it necessarily helps you to decide whether to add a "ferro-" prefix or not.

(as a fun aside, Ni- and Co-rich compositions might also be expected to fuse into magnetic little balls, but these aren't currently known in nature).

19th May 2020 20:32 UTCPierre-Luc Croteau

But Byssolite formula, in the Mindat database, don't list "Fe":

AX2Z5((Si,Al,Ti)8O22)(OH,F,Cl,O)2 

Does it mean, if the result of the fusion is magnetic, that it must include "Fe" in the formula and then, it is not Byssolite?

19th May 2020 22:36 UTCFrank K. Mazdab 🌟 Manager

Hi again Pierre-Luc,

Just a little background here:

That formula is a general formula covering numerous species, not a specific mineral formula (because "byssolite" is as well not a species, but a varietal name for a diverse group of pale-colored "furry" amphiboles).

So actually, the Fe required for a specific species like actinolite or ferro-anthophyllite is hidden within the "Z". Z isn't a specific element, but an abbreviation for all the ions of similar size that fit into that particular set of sites that all happen to be surrounded by six nearby oxygen atoms. These elements are usually Mg and Fe2+, but Al, Ti, Fe3+, Mn2+, Mn3+, Li and rarer elements can go in there too.

Similarly, the "X" also isn't a specific element either, and instead is a generic symbol representing the slightly larger ions that prefer to have eight oxygens surround them in an amphibole structure. These X elements are commonly Ca and Na, but Mg, Fe2+, Mn2+ and Li can also fit in there. Note the overlap of some elements between the smaller Z site and the slightly larger X site... the elements that show up in both lists sit just on the nominal size boundary where they can occur either in the smaller site alone, or in the smaller site plus with extra slopped over into the slightly larger site. Al is similar in that it can sit in the small silicon site (that's why the general formula shows (Si, Al)), or in the slightly larger Z site. But it's too small to ever occur in the still larger X site.

If you click on the amphibole supergroup link on the byssolite page, you'll get a more detailed overview of what elements typically occur in what sites. But to summarize, "byssolite" may quite likely have some Fe in it. But we just couldn't give it a more detailed formula because "byssolite" isn't a specific mineral, but just a collector's name for a whole family of furry amphiboles, some of which might have some Fe and some that probably don't.

22nd May 2020 14:01 UTCPierre-Luc Croteau

Oh wow! Your answer was more than expected, you are a very good vulgarizer! Thank you again and again!

10th Jan 2020 19:29 UTCPaul Brandes 🌟 Manager

Just a thought, but a specimen I have from near Black Lake is chrysotile asbestos that doesn't look too dissimilar to your specimen, Pierre.

10th Jan 2020 21:03 UTCPierre-Luc Croteau

Thanks Paul, but I've already check for Chrysotile, which not fuse anyway - according to the readings I have made!
 
Mineral and/or Locality  
Mindat Discussions Facebook Logo Instagram Logo Discord Logo
Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 25, 2024 11:54:48
Go to top of page