Rust oysters

[tomferry]

I have been searching for these rust oysters for a while now and finally came across some , I have not been able to find out any information about them also their true name so I am unsure if this title needs amending ? These where found in a Slate mine I would say at a medium depth level their was also a good draft / well ventilated the air felt cool and fresh also I would say the location these where ?Growing was moist ? the wall was very damp , we walked hundreds of meters of this  pipe and they was only on 2 areas of this pipe  which probably was 2 x 1 metre sections .

Has anyone ever found these in any caves where old fashioned steel scaffolding had been installed ? Or are these only mine related ?

Would be grateful for any information or links to Previous topics about this .

Tom

Chris shall attach a image kindly later on .

 

[NewStuff]

I found more the other week in Cambrian slate mine. No idea if they've been found on steel in caves. The metal would need to be in there for a long time, given the abandonment dates of Cambrian and Moel Fferna, the other place I've found them.

 

[ChrisJC]

Here's one pic...

 

[rjw]

I'm sure there was a topic in the aditnow forums on this. There are a number of photos which are referred to as "rust shells". But any threads in the forums will be unavailable for the time being.

I think.

 

[tomferry]

I been thinking about these strange little objects .


The only ways I can see them really being able to form is if they was laying dormant on the steel ? or could it be a reaction some how to the water dripping from the roof causing this shell type crustaceans?  I am more thinking the later  :-\

 

[Brains]

Seen lots over the years in different places. My opinion FWIW is that it's a combination of bacterial and chemical reaction. Surface lamination from manufacturing within the metal has trapped impurities that are later exploited to bubble up in these. I believe when complete they would be full of acidic liquid, with low oxygen and bacteria. The iron would be present as Fe++ At the surface this would oxidise to Fe+++ and form a crust or shell of oxides and or carbonate (siderite).
Very interesting and curious features, deserving of more research

 

[pwhole]

There's a fabulous example by  Willy Eckerslyke on AditNow, but sadly only those registered previously to closedown can see it:

https://www.aditnow.co.uk/Photo/Rusticles_105434/

 

[Cantclimbtom]

  I was previously logged in, but maybe a cookie has expired or something because now I'm locked out of AN    I think I remember seeing those pics though, they were great if they're what I think you linked

 

[pwhole]

I could copy it, but it does say 'Don't' on the AditNow site! Maybe Roy will let me?

 

[tomferry]

I bet I have found the biggest single rust oyster yet though  :ras: 

I have photo proof is a crap photo but it shows it?s a good size 

 

[RobinGriffiths]

B52s consider rename.

 

[Paul Marvin]

I could copy it, but it does say 'Don't' on the AditNow site! Maybe Roy will let me?

Not Roy you need to ask its the photographer buddy 

 

[Brains]

Some pics of "Rusticles" or "Rust Oysters" or whatever you want to call them...
First one is broken

 

[Brains]

And another one...

 

[The_Bogieman]

Pretty certain this is common or garden electrolytic corrosion of iron. Used to see a lot when I was a marine engineer. You'g get a raised shell of rust which when prodded would release a foul smelling, acidic liquor. Underneath would be a deep corrosion pit, even the base material being holed... In the presence of water - especially salt water with good conductivity, plus oxygen from the air, you get anodes and cathodes forming with areas of iron oxide and the raw iron (steel). An electric current flows and hey presto, a self sustaining corrosion cell is formed which gives a hardish shell over a liquid, acidic solution, over a developing pit. See this link:
https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_Chemistry_-_The_Central_Science_(Brown_et_al.)/20%3A_Electrochemistry/20.8%3A_Corrosion

 

[ChrisJC]

Tom and I did some investigation yesterday. I'm not sure that explanation is quite right. For two reasons:
1. They form upside down. See picture below. Surely this means any water will just run out and disturb the reaction.
2. We opened a perfectly formed one. It was full of water, but not foul smelling by any means. No smell at all!

Chris.

 

[tomferry]

Correct I quit smoking 11 weeks ago my smell at the moment is picking up every slight smell all I got of this was clean water .  the one We found was on a ladder way out of reach of traffic coming in , the design and location made this a perfect candidate.

 

[ILT]

Found them growing in every direction on rails (most commonly), shovels, pipework, corrugated steel. From the 'classic' cockle shell shape through shapes that look like bracken fronds. Mostly less than about 30mm diameter but a few isolated much larger examples (though never found any really large one that had both sides attached). Never found any that had any smell (other than of rusty iron) or had anything but clear fluid (assumed water) in them. Always in damp environment. Never noticed any growing where water was moving over them or dripping on them.

 

[tomferry]

I think the air flow must be very important also they seem to like a mist environment.

 

[ILT]

In only one place with rust shells have I seen 'mist' and there were fewer close to that than there were further away