Some lampworkers use Kugler Iris Gold to get this gold metallic look. I have used it too, but with disastrous results. The Kugler c.o.e., which is 90 I think, is so far from the Effetre c.o.e. 104 that most of it cracked off my beads. Maybe I'm not aware of other 104 gold glasses that are out there, but this M-166 will be the one I use from now on.