Topic: MDG or Craft Glass Ltd. green bottle , was silver foil used in the decoration ?

[Baked_Beans]

I'm just throwing this in for a possible thought as I know nothing about the sort of chemical reactions with glass.

Just from an artistic point of view and this is only my personal opinion , which could be very wrong ....nevertheless I believe there was a real attempt to produce a glass that copied marble . Perhaps a combination of silver leaf and silver chloride would achieve a very good likeness to the green Irish marble seen above. There is the grid pattern which is seen in so many different marbles  . Could it be that the silver chloride powder could have dulled the silver leaf ? But I do understand that compacted powder could perhaps produce a similar break-up effect . 

[chopin-liszt]

I'm not really seeing any white anywhere, and not in any pieces I have. What I do "see" (remembering that the brain constructs what "we see" for us, rather than actually telling us exactly what we do see) is streaks of paler stuff, which could be from the silver being stretched. When silver chloride gets hot, it melts into a liquid, it does not stay as a powder.

Silver reacts with glass at much lower temperatures than molten glass can reach, it was a big problem, and one William Walker and Michael Harris eventually solved while working on Azurene. I have a couple of very early bits from before it was sorted and they show a white appearance. I don't have any pics to hand.

I don't know how they avoided the high temperatures that cause reactions in Murano, or if they have ever made the technique/method public knowledge.

[Baked_Beans]

Just as a side note the altar of St.John's Co-Cathedral in Valletta   Malta is made of Lapis Lazuli and other rare marbles ..I haven't seen it myself but could have been an inspiration perhaps ?

[chopin-liszt]

I think it's more likely they were just experimenting with effects, but glass has always been used to mimic precious stones.

The very first bit of Earthtones I saw (and the second bit of Mdina I bought) was something I originally assumed to have been carved from a huge lump of agate.

[Lustrousstone]

But does your "silver" shine, because silver foil in glass most certainly does and it wouldn't give yellow if it did react. Those white bits on Mike's bottle don't shine.

[Baked_Beans]

I agree ! Agate it is  ....if I ever have the chance of visiting Malta I shall go on a pilgrimage to St.Johns Co-Cathedral and have a good look at all the different  marbles ... 

[Baked_Beans]

If the combination silver chloride (plus leaf)  dulled the silver leaf then it wouldn't shine ....perhaps 

[chopin-liszt]

Silver foil does give rise to both yellow and ochre coloured glass.
I'll take some pics of my really early experimental Azurene to show what it can look like, but that's when the foil has been applied to the surface.
If foil has ended up encased, it could react with both layers of glass and the top layer might dull any shine.

[Lustrousstone]

Silver foil on the surface oxidises, i.e., tarnishes, which is why it looks yellow. It doesn't react with the glass

[chopin-liszt]

Silver will oxidise (tarnish) when it's on the surface, after the glass has cooled and is sitting on shelves, but it will react with the glass if it is hot enough.
While the glass is very hot and molten and being worked, I don't think there is a lot of oxygen around in all that heat. I have always thought that any bubbles which appeared were the chlorine.
I've certainly never seen oxidised silver *inside* glass - it would be black, wouldn't it?

I do need to check at what temperature the silver and chloride seperate, but I don't think it's astronomically high. I've searched a bit.
It melts at 455 degrees C. It will dissociate into silver and chlorine slowly but spontaneously at room temperature.
(I can't find any mention of temperature dissociation, just solubility.)