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Basement Minerals

Posted by Reiner Mielke  
Reiner Mielke August 17, 2011 07:02PM
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?

Edited 1 time(s). Last edit at 08/17/2011 07:03PM by Reiner Mielke.
open | download - Basement UK.JPG (342 KB)
open | download - BasementUKcloseupA.JPG (141.1 KB)
open | download - BasementUKcloseupB.JPG (97.9 KB)
Jolyon & Katya Ralph August 17, 2011 07:41PM
> 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.
Rob Woodside August 23, 2011 05:42PM
The colour is OK for Xanthoconite but the habit is not convincing. Perhaps an arsenate of some sort?
Reiner Mielke August 23, 2011 10:22PM
I'll send it off for EDS analysis. The crystals are very thin and the slightest breeze causes them to shake.
Howard Heitner August 29, 2011 02:26AM
Are you absolutely sure that the crystals were not there when you put the samples in storage? Perhaps you did not notice them.
Reiner Mielke August 29, 2011 01:23PM
Absolutely certain they really stand out. Besides they are far too fragile to have possibly survived a washing.

Edited 1 time(s). Last edit at 08/29/2011 01:24PM by Reiner Mielke.
Paul Brandes August 30, 2011 01:10AM
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)
Howard Heitner August 30, 2011 08:37AM
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.
Rob Woodside August 30, 2011 06:19PM
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.
Uwe Ludwig August 30, 2011 08:20PM
It may be Claudetite.

Uwe Ludwig
Uwe Kolitsch August 31, 2011 08:26AM
Can't be claudetite (which is colourless or white).
Tomas Husdal August 31, 2011 11:32AM
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...
Uwe Ludwig August 31, 2011 06:01PM
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
Evan Johnson (2) August 31, 2011 06:34PM
Are claudetite crystals (colour notwithstanding) generally tinsellike and flexible as described?
Uwe Ludwig September 03, 2011 08:33AM
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
Reiner Mielke September 03, 2011 02:09PM
Hello Tomas,

Great idea, I think I will start a mineral garden in my backyard.
Spencer Ivan Mather September 03, 2011 03:30PM
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?


Thank you. Spencer.
Alfredo Petrov September 03, 2011 03:53PM
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!
Reiner Mielke September 03, 2011 04:10PM
Hello Spencer,

Take a picture so even if it gets destroyed you still have a record of it, would love to see it.
Reiner Mielke September 21, 2011 12:49AM
Got the EDS results back, looks like it is acanthite! But it is transparent!!! Could it be a silver sulphate?

Edited 2 time(s). Last edit at 09/21/2011 12:52AM by Reiner Mielke.
open | download - Basement Mineral.jpg (31.6 KB)
Reiner Mielke September 21, 2011 07:00PM
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.
Bart Cannon September 21, 2011 08:49PM
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 ?
Reiner Mielke September 21, 2011 09:52PM
Strange thing is it is not on silver but arsenides, the silver is about a millimeter away and has no fuzz on it.
Bart Cannon September 21, 2011 10:52PM
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.
Bart Cannon September 22, 2011 10:39AM
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.
Reiner Mielke September 22, 2011 12:04PM
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.
Spencer Ivan Mather September 22, 2011 02:42PM
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.

Van King September 22, 2011 09:49PM
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".

Best Wishes, Van King
Dana Morong September 24, 2011 02:50PM
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.
Reiner Mielke November 30, 2011 01:37AM
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.
Rock Currier November 30, 2011 01:44AM
The evil men do lives after, the good is oft interred with their bones.

Rock Currier
Crystals not pistols.
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