That is a very hard question. Rauchtopaz was very popular in Germany (Friedrich Kristall, Joska Bodenmais, Zwiesel, Gralglashütte, WMF Eislingen, Eisch) but also in Holland (Kristalunie Maastricht) and various producers in Belgium. I have a full shelf of unidentified smoke - all vaguely produced between the early 30s and the late 60s ("the murky years") and collected in the vague hope that maybe one day related colours might reveal the producer. So far, no luck - also because there are colour variations and production inconsistencies....