20's czech brooch

So here is another brooch I wanted to post. I've had it for a while and I got it from a lot I once bought. It looks similar tho the brooch with the pink glass from my grandmother I posted a while ago. I think its made in the twenties or thirties and maybe its czech. Its rhodium plated and it has a safety clasp. It also has a tiny mark that I really don't know. The mark looks like some sort of X.
(see second and third picture). If anyone knows this mark, help would be really appreciated.
I hope you enjoy!