Thanks for the informations, IĀ“ll try to find out more..
Very nice colour and quality, but in detail I think proportions and the cutting look a bit different from the 50s-Franz Burkert-version; looks like a modern interpretation of a design-classic. Wonder, who made this one.
Meanwhile I searched for a late 50s-photograph (please excuse the poor picture-quality) of an ashtray with the Hessenglas-overlay-rainbow-colour. The one I found is a piece produced by Josef Mitlehner at Kronberg (Hesse nearby Oberursel) and sold by Hesse Glasworks (HG). Mitlehner originated from bohemian Maxov (Unter Maxdorf) nearby Josefuvdul too and was also one founding member of Hesse Glasworks. The designelements relate also definately to the earlier Franz Burkert ashtray, which also was known with the rainbow colour. This piece can be found at Glasmuseum Gernheim/Germany.
The other pictures show another copy with the efforts to imitate the Hessenglas-rainbow-colour-reflections by glewing on a foil at the bottom.