Topic: French Spanish or Portuguese glassworks using manganese in 1920-40

[Angela B]

Can someone help Tom Trizzo with a question relating to Glass Fishing Floats The question is, do you know of either a French, Portugese or possibly Spanish glass house that was producing in the time period 1920-1940, who often used Manganese in their mix to produce clear glass?

The reason Tom asks is that glass floats from that time period continue to exhibit amethyst in the mix.  As he continues to research, it has become evident that the amethyst use in floats was coming from one place, and as Tom said "I sure would like to pin that country or glass house down!"

 (Tom's article on fishing floats is at  http://www.theglassmuseum.com/fishingfloats.htm)

I hope someone can help.