Micromosaics are a type of mosaic created from tiny fragments of glass, called tesserae. The tesserae are mosaic pieces made from an opaque vitreous glass or enamel in a multitude of colors called smalto. The smalto is pulled into rods or threads, called filati (spun enamel), and then left to cool.
Thank you, you routed me to the right direction. I've just searched "micro-mosaic" within this forum and found other forumers have got similar jewels. Here we can read a good description of this technique
It comes from Italy for sure. It's a pity it's so ruined and I guess there isn't any way to restore it by a "domestic" work, I mean not by a professional, is there?
Well, I think I'll try to sell it for 20-30 euros.
PS - How can I contact a moderator to ask to move this thread to "Antique & Vintage Jewelry" area?