I shall go squint with a loupe. Nope, nothing else, just the wee town marks which @Bronwen cleverly spotted. All of that plaited work is individual, too, not cast or moulded. The whole thing is hand worked. it needs a clean, which I shall do very gently. The stones aren't foil backed, either, they're really nice under magnification. But mucky. I'd agree on Czech glass being generally exported even in the Soviet era: I see so much 60s and 70s Sklo here.
Solder will be tricky... I had once some success with “solder it silver bearing paste”, but now I can’t fix anything with it anymore Now, I use UV curing resin, hard type, with an UV lamp used for nail art. https://www.etsy.com/fr/listing/587576623/clear-transparent-uv-resin Been able to fix a C clasp on a gold brooch with that, as well as a belt clasp slide. You need to well degrease the intended joint area with acetone and file it a little for better grip of the resin. Not sure though if the weight and effort during wearing will be supported by the repair, but worth a try
I had the same. I thought I was getting more clumsy, but maybe they changed the composition? (As well as me getting more clumsy ) Wow! Worth a try then. Thanks for the link.