Art Nouveau brooch of a lady, Jugendstil/Mucha style, not marked.
I've seen two listing on ebay which sold for £50-70, they don't seem to know much about them though. I could be wrong but, judging from the clasp it seems like it's not as old as it looks from the front. One ebayer says he tested it for silver and it passed, just seems odd that it's not marked. There's a variant of the brooch design which cuts out the outside edge. The clasp on that is different though.
https://uk.pinterest.com/pin/167125836147149945/
