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 HelpBasement Minerals

17th Aug 2011 20:02 UTCReiner Mielke Expert

01421030016043397336126.jpg
I was going through some egg cartons with silver from Cobalt, Ontario that I had stored in the basement (60-70% humidity) for 3 years and discovered something had grown on one specimen. The crystals are thin as tinsle ( and flexible) and very shiny up to .75mm long in radiating groups up to 1.5mm wide. Anyone have any ideas what these might be? The specimens had only been washed in water ( 3 yrs ago) and consist of wire silver with a small amount of some sort of fine grained arsenide on one end from which the crystals have grown. My guess is xanthoconite based on the color and form? Also would this be a valid mineral species?
02817660016043397333067.jpg
05701980014960136951805.jpg

17th Aug 2011 20:41 UTCJolyon Ralph Founder

> Also would this be a valid mineral species?


sadly not by current official definitions. But how you choose to classify it is entirely up to you! Nice find.

23rd Aug 2011 18:42 UTCRob Woodside 🌟 Manager

The colour is OK for Xanthoconite but the habit is not convincing. Perhaps an arsenate of some sort?

23rd Aug 2011 23:22 UTCReiner Mielke Expert

I'll send it off for EDS analysis. The crystals are very thin and the slightest breeze causes them to shake.

29th Aug 2011 03:26 UTCHoward Heitner

Are you absolutely sure that the crystals were not there when you put the samples in storage? Perhaps you did not notice them.

29th Aug 2011 14:23 UTCReiner Mielke Expert

Absolutely certain they really stand out. Besides they are far too fragile to have possibly survived a washing.

30th Aug 2011 02:10 UTCPaul Brandes 🌟 Manager

Shows where my mind is.

When I saw "Basement Minerals", first thing I thought of was the crystalline rocks/minerals of the Canadian Shield..... B)

30th Aug 2011 09:37 UTCHoward Heitner

Now I know that anything resulting from "human activity" is not considered a mineral. My question is: if a secondary compound is formed when a mineral formed deep in the crust is brought to the surface and exposed to air and water, does it matter if the original mineral was brought to the surface by faulting and erosion or by human mining? The chemical history of the new compound is the same. This is especially true if the "human activity" is not obvious. Something formed in slag or a coating on an old bullet is one thing, but this is really a different case.

30th Aug 2011 19:19 UTCRob Woodside 🌟 Manager

Feathery Acanthites often form on Beaverdell Ag minerals. If this happens in rock the Acanthite is a mineral. If it happens post mining it is merely cabinet growth and not a "valid" mineral. There is absolutely no difference between the mineral and the cabinet growth.


We seem to be starting a new geologic age with human intervention and when this is accepted maybe the IMA will accept anthropogenic artifacts as minerals.

30th Aug 2011 21:20 UTCUwe Ludwig

It may be Claudetite.


Uwe Ludwig

31st Aug 2011 09:26 UTCUwe Kolitsch Manager

Can't be claudetite (which is colourless or white).

31st Aug 2011 12:32 UTCTomas Husdal Expert

Drawing the line between "natural" minerals and anthropogenic substances is not easy. Post mining compounds formed on untreated dump material are considered valid mineral species.

I will, on purpose, place boulders rich in REE-minerals on the seashore, and return in some years to look for new minerals with REE, Na and Cl...

31st Aug 2011 19:01 UTCUwe Ludwig

Yes Uwe, normally Claudetite is colourless. However, the pieces have been treated before storing and who knows the conditions in a humid basement? I saw a lot of coloured minerals which are normally colourless. According to my opinion the colour is no certain criterion of a mineral.


Uwe Ludwig

31st Aug 2011 19:34 UTCEvan Johnson

Are claudetite crystals (colour notwithstanding) generally tinsellike and flexible as described?

3rd Sep 2011 09:33 UTCUwe Ludwig

Claudetite is not always colourless (see ID 348684 and ID 348680) and it is soft and flexible according to the literature I read.


Uwe Ludwig

3rd Sep 2011 15:09 UTCReiner Mielke Expert

Hello Tomas,


Great idea, I think I will start a mineral garden in my backyard.

3rd Sep 2011 16:30 UTCSpencer Ivan Mather

About twenty years ago I put some mercury into an aluminium can with a screw top, then last year when I found it in my shed I opened it, and found to my surprise that there was no mercury left, instead there where several shiney silvery-grey crystals, could anyone tell me what has gone on here, and what the crystals might be?


email address.........garnets@hotmail.co.uk


Thank you. Spencer.

3rd Sep 2011 16:53 UTCAlfredo Petrov Manager

Aluminium amalgam has formed, I suppose? Lovely find, in crystal form!


But since you've opened it and exposed it to the air, it will get destroyed - Seal it up again, quick!

3rd Sep 2011 17:10 UTCReiner Mielke Expert

Hello Spencer,


Take a picture so even if it gets destroyed you still have a record of it, would love to see it.

21st Sep 2011 01:49 UTCReiner Mielke Expert

04474270016043397337450.jpg
Got the EDS results back, looks like it is acanthite! But it is transparent!!! Could it be a silver sulphate?

21st Sep 2011 20:00 UTCReiner Mielke Expert

Had a closer look at the crystals, the brown color is just a tarnish and the crystals are opaque, so it looks like it is primary acanthite.

21st Sep 2011 21:49 UTCBart Cannon

This is acanthite "fuzz", and is very common, expecially when silver, silver sulfides and sulfosalts are enclosed in the gentle climate of a drawer or box.


Materials science people call the process "gettering".


Copper and silver draw sulfur out of the atmosphere, and especially so in a partial vacuum.


If I leave metallic copper or silver in the probe for a few days those metals get coated with sulfides.


Tarnish on silver teapots might have the acicular habit if air currents around the house weren't killing the delicate structures.


I would agree with Rob that acanthite fuzz is not a mineral, but please bring back the Laurium minerals to full status. Human beings are 100% natural creatures. Just like bacteria which are responsible for the formation of most of the secondary minerals we all love.


I draw the line at engineered materials such as alloys. But I think this whole area of discourse is kind of wobbly.


I have seen beautiful crystals of synthetic quartz, crocoite, anglesite etc. Them things are minerals.


Mandarino is dead. Can't we reverse his decision on Laurium? With a respectful footnote ?

21st Sep 2011 22:52 UTCReiner Mielke Expert

Strange thing is it is not on silver but arsenides, the silver is about a millimeter away and has no fuzz on it.

21st Sep 2011 23:52 UTCBart Cannon

That surprises me, but nucleation sites are a bit "fuzzy" themselves.


I wonder if there could be a little native silver intergrown with the arsenides.


This could be a new category of minerals to collect and curate.


There are a host of sulfates that grow on pyrrhotite and marcasite in the drawers. Some beautiful and delicate.


My favorite off center collecting category is "mineral creations".


My first experience was chalcanthite. No glue needed. No artistic skill needed either, so I put them in the "Low" categorty.


I have a fantastic "created" leadhillite from Tiger, AZ. It is a PERFECT thumbnail. I will never sell it, and I will never sell my texasites.

22nd Sep 2011 11:39 UTCBart Cannon

I decided to look through my mineral and element collection for acanthite and copper sulfide fuzz or whiskers.


I can't find any on simple native copper or native silver specimens. Just tarnish.


The only time I see them is on specimens with silver bearing minerals associated with other sulfides or sulfiur bearing selenides.


Could Thiobacillus (bacteria) be involved ? Bacteria need moisture. Is acanthite fuzz more prevalent in moist climates ?


One of my first commercial accounts was with Sunstrand Data and Allied Signal formerly of Redmond, Washington. They brought me their failed $8,000 miniature accelerometers. The same acceleromters used in the Sea Snake missiles that took down that Iranian passenger jet long ago.


The accelerometers were a wonder of technoloty, but kept failing because of embrittlement at the lead pad / copper coil wire joint on the thin quartz reed. The mechanism was in a vacuum, and extremely elegant. The lead pads all showed tiny arborscent copper sulfide crystals. The O-Rings used to seal the assembly contained 6% sulfur. I suggested they used a low sulfur polyurethane O-ring, but 15 years later my last job looked just like the first, and they were still using sulfur bearing O-rings. I could never figure out why they bothered to hire me for at least 100 analyses.


I had an engineer friend at Boeing whose job was to perfect the growth of tungsten "whiskers". That sort of thing is now part of the trendy buzz term known as nanotechnology. I wonder if acanthite whiskers might become a big play in that field.

22nd Sep 2011 13:04 UTCReiner Mielke Expert

Hello Bart,


The sample I had was in an egg carton with 11 other silver samples none of which had any fuzz. Don't know what made the one different from the others other than it was the only one with a bit of arsenide. Must require some very unique conditions to grow.


"I could never figure out why they bothered to hire me for at least 100 analyses." Guess they just wanted to know why they failed and not how to correct the problem. But then maybe it isn't a problem, I mean they could make cars that don't rust but they don't because there is more money to made with cars that do rust. Such is the world of capitalism.

22nd Sep 2011 15:42 UTCSpencer Ivan Mather

Sorry guys, but after I opened the tin of mercury (crystals) or Aluminium amalgam, I threw it in the bin for toxic chemicals. By the way, the crystals were about 2cm long and 4mm wide, but before I could see what crystal system they belonged to they just slowley melted.


Spencer.

22nd Sep 2011 22:49 UTCVandall Thomas King Manager

When I was teaching high school science, I put some copper sulfate in an aluminum cake pan. I soon remembered that the reaction series would cause a replacement of the copper ions in solution. I continued to let the solution evaporate and got copper inclusions in copper sulfate crystals. The cake pan was, of course, "history".

24th Sep 2011 15:50 UTCDana Morong

I suspect that this growth may be the phenomenon once called “Moss” growths (such as “moss copper,” “moss silver,” or “moss gold”), not all of which are elemental, but some of which may be sulfides. I encountered several (over a dozen) as apparent additions in an old micromount collection, in which it seemed that the original collector did not notice them, and apparently they may have grown during storage. They seemed to occur mostly on sulfides. I am not certain as to how they grow (the chemistry of it), but that it is a real phenomenon I am certain. Several articles in periodicals I have seen and read on the subject:


Chemical News, 1877, volume 35:

Feb. 16, pages 68-71 On the Formation of Moss Gold and Silver

(Archibald Liversidge)

March 23, pp. 117-118 On the Formation of “Moss Copper” (W. M. Hutchings)

April 6, pp. 144-145 Moss Copper, &c. (T. A. Readwin, letter)

April 13, p. 154. Moss Copper, &c. (J. H. Collins)

May 4, pp.180-182 Formation of Moss Copper, &c. (W. M. Hutchings)

May 4, pp. 186-187 Moss-Copper, &c. (T. A. Readwin)

May 11, pp. 195-196 Formation of Moss-Copper, &c. (T. A. Readwin)


Mining and Metallurgy, 1907, Amer. Inst. of M., M., P. E., p. 214


“Growing Wire Silvers” letter by Don Edwards, of Tideswell, UK, in Letters, in Mineralogical Record, January-February 2001, v.32, #1, 72-73.


“On a Fibrous Metallic Copper” by James Smithson, 1820, from Thomson’s Annals of Philosophy, Vol. XVI, 1820, p. 46, and reprinted in The Scientific Writings of James Smithson, edited by William J. Rhees, 1879, in Smithsonian Miscellaneous Collections, #327, in volume 21, p. 68-71.


“On some Capillary Metallic Tin” by James Smithson, 1821, from Thomson’s Annals of Philosophy, Vol. XII, 1821, or New Series Vol. I, p.271, reprinted in The Scientific Writings of James Smithson, edited by William J. Rhees, 1879, in Smithsonian Miscellaneous Collections, #327, in volume 21, p.75.


There are other references which I have not accessed yet:

Principles of Extractive Metallurgy, Fathi Habashi, Volume 3: Pyrometallurgy, 1969, page 201

Metallurgy: The Art of Extracting Metals from their Ores (John Percy, 1861, 596 pages,

(moss copper, pp. 342-350... & beyond)

The Ore Deposits of the United States and Canada (James Furman Kemp, 1900, 481 pages)

Handbook of Metallurgy, Carl Schnabel, Henry Louis, 1898


I do not know whether Ramdohr’s large volume The Ore Minerals and Their Intergrowths would have any mention of this phenomenon, although I doubt it, as this book is fairly recent, and the phenomenon attracted attention mainly many decades ago; it does not seem to attract academic attention now, perhaps because it has too little appeal to grantors of graduate school projects, and also possibly because there is doubt about the growth’s status as minerals. One of the most recent mentions, and the most accessible, is the letter (mentioned) in Mineralogical Record in 2001 (volume 32), on pages 72-73.


I would be most interested in learning more about this phenomenon, in other references to it in the literature, and in corresponding with others who are interested in it.

-----

30th Nov 2011 01:37 UTCReiner Mielke Expert

Found another even better specimen of this material in my basement yesterday and much to my amazement someone uploaded a "natural" one that looks exactly like my basement acanthite. http://www.mindat.org/photo-427924.html

30th Nov 2011 01:44 UTCRock Currier Expert

The evil men do lives after, the good is oft interred with their bones.
 
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: March 28, 2024 12:41:08
Go to top of page