I'm so sorry, today was a crazy day, I meant to get back to you sooner...the necklace is 20" long, so 1950s? The color is definitely a Mid Century favorite, but its pretty ubiquitous across eras, too. I'm willing to bet they're Czech, almost all of the glass beads in this box were Czech, but I'd love to hear your thoughts. I think you're right about the acid bath, they are very soft and satiny. I'm thrilled to have put some of the pieces together! -Melissa