Today these are called Fired Bronze colors. Supra was a term started in 80s/90s and with coatings like this the technology has been developed for seed beads. In general, seed beads being small have a small surface area and less chance for atmospheric conditions to bother the surface. These coating's popularity and affordability have gotten so popular they have be used on beads with bigger surface area: pressed and Fire polish. There is a sense of next generation technology with these items. For Miyuki they have terms like Duracoat and permanent finish and Czech have had Sol Gel and Terra colors. Each time perhaps an improvement regardless of brand but Permanent finish is a marketing term more than an actuality. The intent is there but with sweat, acid , sun and heat....technology is not fool proof: each coating is meant to be more or less resistant but application and use varies and so do results.