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Basement Minerals

Posted by Reiner Mielke  
Basement Minerals
August 17, 2011 08:02PM
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 08:03PM by Reiner Mielke.
open | download - Basement UK.JPG (342 KB)
open | download - BasementUKcloseupA.JPG (141.1 KB)
open | download - BasementUKcloseupB.JPG (97.9 KB)
avatar Re: Basement Minerals
August 17, 2011 08:41PM
> 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.
avatar Re: Basement Minerals
August 23, 2011 06:42PM
The colour is OK for Xanthoconite but the habit is not convincing. Perhaps an arsenate of some sort?
Re: Basement Minerals
August 23, 2011 11:22PM
I'll send it off for EDS analysis. The crystals are very thin and the slightest breeze causes them to shake.
Re: Basement Minerals
August 29, 2011 03:26AM
Are you absolutely sure that the crystals were not there when you put the samples in storage? Perhaps you did not notice them.
Re: Basement Minerals
August 29, 2011 02:23PM
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 02:24PM by Reiner Mielke.
avatar Re: Basement Minerals
August 30, 2011 02:10AM
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)
Re: Basement Minerals
August 30, 2011 09:37AM
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.
avatar Re: Basement Minerals
August 30, 2011 07:19PM
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.
Re: Basement Minerals
August 30, 2011 09:20PM
It may be Claudetite.

Uwe Ludwig
Re: Basement Minerals
August 31, 2011 09:26AM
Can't be claudetite (which is colourless or white).
Re: Basement Minerals
August 31, 2011 12:32PM
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...
Re: Basement Minerals
August 31, 2011 07:01PM
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
Re: Basement Minerals
August 31, 2011 07:34PM
Are claudetite crystals (colour notwithstanding) generally tinsellike and flexible as described?
Re: Basement Minerals
September 03, 2011 09:33AM
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
Re: Basement Minerals
September 03, 2011 03:09PM
Hello Tomas,

Great idea, I think I will start a mineral garden in my backyard.
Re: Basement Minerals
September 03, 2011 04:30PM
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.
Re: Basement Minerals
September 03, 2011 04:53PM
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!
Re: Basement Minerals
September 03, 2011 05:10PM
Hello Spencer,

Take a picture so even if it gets destroyed you still have a record of it, would love to see it.
Re: Basement Minerals
September 21, 2011 01:49AM
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 01:52AM by Reiner Mielke.
open | download - Basement Mineral.jpg (31.6 KB)

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