Manof,The yellow/purple swirls are hard to find here and the purple/green ones are easy to come by,do you find the white-red blue swirls in England?
Steph,when I see a marble which I think might be foreign,I prefer to wait out on your reaction because I do not want to complicate it.
On the marbles of Shell,I was not sure wether America has made those pastel colored swirls,i only knew that Veiligglas made them,now I know America made them aswell.