I used all the information to quickly home in on what I (inadvertently) purchased. I believe the beads are coated with a sol-gel coating of unknown composition. I can peel some of it off in fairly flexible pieces, so it is probably at least partly organic. Could have inorganic components for color and/or durability. It's kind of too bad that glass chemistry is not being used exclusively to make beads that are solid glass. Beaders are gaining a larger range of artistic expression but sacrificing the longevity of their work. I doubt any of these coatings will be around in 100 years unless the beadwork is carefully conserved.

I think I'll continue to look for antique or at least vintage solid glass beads to complement the ones I have. They are a combination of a large purple "Peking glass" - or so I think - bead with some dusky plum purple "pineapples".