Topic: Blue Uranium Glass Butter Dish?

[Paul S.]

I could be wrong Michael, but I think your glow stands a good chance of being from a manganese content  -  it doesn't look bright enough to be from uranium.

[rocco]

Sorry, l wasn't clear - these post war blue pieces certainly do not contain Uranium...

Michael

[Paul S.]

thanks Michael  -  I'd assumed, obviously wrongly, that you were suggesting your blue Sklo Union vase contained uranium - a misunderstanding all round.             I think your vase gives support to Christine's comment that manganese was often added to coloured glass - and though I'm unsure, technically, as to why this was the case, can think only that all glass - whether clear or coloured - benefited from the addition of manganese as a de-colourant.

[NevB]

It would be interesting to actually know at what percentage Manganese ceases to be a de-colourant and becomes a colourant. I suggested over 1% but don't know for sure.

[flying free]

I cannot really comment on whether the piece in question is Uranium glass or not, but I noticed that the blue Sklo Union pressed glass items show a strong yellow-green glow under UV (see pic).

Michael

My blue Sklo Union ashtray does too.  It gives off a very green fuzzy glow.  So does some of my antique Bohemian glass.  I think it's something in the make up of their glass from the area to be honest.  If I'm in doubt about an old piece and it glows that colour my first thoughts are Bohemian.  If it's pale orange/salmon I think Saint Louis or Russian.  And if it's a yellow I generally think French old at first.

[Paul S.]

so are you suggesting m that these orange/salmon/yellow reactions are likely to indicate a selenium content  -  I always had yellows down as being likely selenium.

[flying free]

No.  Not at all.

I'm just saying when I use a Uv Light on the clear glass that's what I find and the avenue it makes me explore for country of maker.  I've absolutely no idea what is in the clear glass to make it have that colour.

[Paul S.]

sure  -  can say that over the years whenever I've found a piece of what I think is Continental glass, the tint that the glass gives off is often of a very slight dull amber/yellow  -  not sufficient to suggest selenium though.      When selenium is present, it gives a far stronger orange/yellow reaction.

[flying free]

To be honest Paul it's such a faint reaction that it's hardly there, but if you've compared enough you see it somehow.
It just an easy guide for me to start looking.  I've absolutely no thoughts on how it occurs and could never use it as an identification though.

m

[Paul S.]

I suppose there's always the possibility that clear glass - when deprived of manganese - will give this background dull brownish/faint yellow tinge  -  just a thought.