iridescent lamination in bottles

[Stingray]

Not gold related sorry but thought someone here might be into bottles and could help.

I was cleaning out my shed and came across an old bottle I found diving about 30 years ago under the Albany jetty. I gave it a shake and noticed all this material inside. It looked like cellophane that had gone brittle. I also saw the remains of the cork that had been pushed inside the bottle. Then I washed the outside to get the dust off. When the bottle was wet I could see that the 'cellophane' was actually a coating on the inside and it was flaking off.

Just wondering what it is actually, how it forms and if this a common thing or not. My googling didn't come up with much. Do you find this in the goldfields or is it something to do with saltwater? You will see from the photos that it is almost mirror-like on the side that was attached to the glass, and iridescent but mainly greenish. The other side is tan coloured. I noticed a similar material on another bottle I had found back then, but the bottle is not as old, different glass and it is not as pronounced. Any insights would be appreciated.

Cheers


Cheers

 

[user 4386]

Are the flakes definitely glass? Not something that was in the bottle that has dried out?

 

[aussiefarmer]

I believe it is the dehydrated contents of the bottle.

 

[Stingray]

Thanks for the comments, it sure looks like a sort of mirror coating on the inside, but I don't think it was the contents of the bottle as I found it 10m underwater in the ocean. It had been there for a long time and it was open when I found it. I only noticed the cork had been pushed in the other day. So whatever was in there had long since washed out. Also, it looks like some kind of beverage bottle to me, perhaps whisky? so even if the contents had remained in the bottle somehow and then dried out there shouldn't leave a residue as evenly coated as that. I don't think the flakes are glass, rather some deposit that has accreted onto the surface of the glass - perhaps leached out of the glass and precipitated out? The glass is coloured green - could that be chromium?

 

[user 4386]

Solarization - the effect of sunlight (UV light) on glass that contains impurities such as manganese results in it becoming green, brown or purple over time. Less common after WW1 as less manganese in glass after then in the main. Copper and chromium tracres can do the same.

You still have the same issue if it was something that accreted later or earlier from the contents of the bottle - that it is evenly accreted. If the cork was inside it, it may have been protected from sea water for a long time. A full bottle could explain the evenness of accretion. Not many things react so significantly with glass - what happens when you hold slivers of it in a candle flame (melt? flame colur? burn? nothing?)/

 

[Stingray]

Here is what happens when you put it in a flame. When I crushed it between my fingers at the end it seemed quite crisp and more metallic.
View attachment IMG_3657_compressed.mov
I also put a flake in some HCl. No fizzing or immediate noticeable reaction. After approx 1 minute the clear HCl solution had taken on a yellow greenish tinge and the flake appeared clear when removed from the acid and held up to the light. Photos below.

 

[user 4386]

Not glass then.

 

[Greenhornet_au]

Would you consider polishing the bottle ?

I know of a method but you need a rolling barrel tumbler, glass bottle collector I knew made
his with a bit of pvc pipe, cuphead bolts and endcaps.

Or if you have it a wood lathe or metal lathe.

 

[aussiefarmer]

Spin the bottle with strangers is very rewarding.

 

[Hawkear]

The flame test was a good start. Most metallic elements show characteristic colours under a flame test. The problem with the test made was that it may not have been energetic (hot) enough to excite the electrons to provide a colour emanation.
I'd suggest doing that test again with a hotter gas flame for more definition.

 

[Stingray]

Would you consider polishing the bottle ?

No I hadn't thought of that. It would look pretty cool but before I do anything I want to understand what it is. To that end I have contacted the Marine Archeologists at the WA Museum - I'll let you all know what they say.

Cheers

 

[Greenhornet_au]

A couple of videos to give you the idea.

PVC tube, end caps and copper wire cuttings with a grinding/polishing media, and water.
Make a machine and test it on another old bottle first.
But your hands get sore cutting the wire....

 

[Stingray]

Thanks for that GH, I had no idea there was a bottle cleaning process like that! You would need a shed-load of wire... If I did it it would only be the outside, and I would have to remove the cork otherwise it will take off all the shiny stuff...

Anyway, I received a call from one of the maritime archeologists at the WA Museum. She had tried to respond by email but it kept bouncing so took the time to call which is great. Apparently the glass curator has written me a response as well so I'll pass that on if and when I receive it. In the meantime this is what I gleaned from the Archeologist.

The material in question is glass that has laminated and detached from the bottle. When preserving a bottle from the ocean you need to remove all the salt - desalinate the bottle by repeated and long soakings in fresh water. I would have only rinsed out the bottle when I found it, so there would have been residual salt that had leached into the glass and remained after it had dried. Over the 30 odd years it has been with me the salt has expanded and contracted as humidity changed and caused the inner glass to laminate and detach over time. Similar to onion rings but from the inside. So it is to do with the salt, and only after being dry but exposed to air for a long time and probably why none of you have reported seeing the same thing in bottles from the same era collected on land.

 

[user 4386]

Thanks for that GH, I had no idea there was a bottle cleaning process like that! You would need a shed-load of wire... If I did it it would only be the outside, and I would have to remove the cork otherwise it will take off all the shiny stuff...

Anyway, I received a call from one of the maritime archeologists at the WA Museum. She had tried to respond by email but it kept bouncing so took the time to call which is great. Apparently the glass curator has written me a response as well so I'll pass that on if and when I receive it. In the meantime this is what I gleaned from the Archeologist.

The material in question is glass that has laminated and detached from the bottle. When preserving a bottle from the ocean you need to remove all the salt - desalinate the bottle by repeated and long soakings in fresh water. I would have only rinsed out the bottle when I found it, so there would have been residual salt that had leached into the glass and remained after it had dried. Over the 30 odd years it has been with me the salt has expanded and contracted as humidity changed and caused the inner glass to laminate and detach over time. Similar to onion rings but from the inside. So it is to do with the salt, and only after being dry but exposed to air for a long time and probably why none of you have reported seeing the same thing in bottles from the same era collected on land.

Makes sense - have not seen it myself. So an interesting start!

 

[Greenhornet_au]

Yeah a shed load of wire bits, but I have been deep in thought about that, and I think I have a simple idea.
Will play with it and put it up on the DIY section tomorrow if I find the parts and it works.
I am tempted to try it as a stainless steel pins substitute in my brass tumbler, the copper will have polishing media
embed into the surface of it, so I assume that you would need a set of copper bits for each grade of cutting and polishing media.
If it works I will be trying to cut stainless wire, and heavy solid nylon cord also.

 

[pulsetrain]

Here is what happens when you put it in a flame. When I crushed it between my fingers at the end it seemed quite crisp and more metallic.

I also put a flake in some HCl. No fizzing or immediate noticeable reaction. After approx 1 minute the clear HCl solution had taken on a yellow greenish tinge and the flake appeared clear when removed from the acid and held up to the light. Photos below.

I'm guessing the brown colour on the flakes is just dirt and that there aren't any specific elements responsible for the colours.
"Thin film interference" is probably the effect that is visible.



As for the mirror effect, I'd guess it's due to the inconsistent thickness of the delaminated glass... ridges, pits etc. and there being multiple spots with the right thickness to reflect most wavelengths of visible light.

Here is a bottle I found last year at the beach.
It still contains the original seawater and is mostly full of sand which has prevented a lot of the delaminated glass flaking off. It has some fantastic colours, reminds me of an opal.

 

[Stingray]

Thanks for posting that info Pulsetrain, excellent video and explains exactly what is going on. And that bottle you found is an absolute ripper! Cheers

 

[Stingray]

Hi all, I finally received the advice from the WA Museum. I have also attached the paper for anyone who is interested.

The iridescent colouring you observed on your bottles is indeed due to deterioration of the glass by seawater. After recovery of bottles from the ocean, residual chloride salts (from incomplete desalination) cause the glass surface to undergo cyclic humidification (when the atmosphere is humid). The degradation of glass is also related to its composition and surface structure. Moisture will initiate the dissolution of the glass network (SiO2) or the leaching of network modifiers (dealkinisation) leading to a weakened glass surface. As degradation advances the weakened glass layer separates from the core glass. The iridescence results from the interference of light rays reflected from thin alternating layers of air and weathered glass (the colours disappear if the glass is wet).

If you are interested in the chemistry of glass degradation there are many articles to be found. I have attached an article that I recently came across. Hope it is of interest.


Regards

Carmela Corvaia
Objects Conservator
Materials Conservation Department
WA Museum