Hi. I have a brooch from Art Nouveau period. Its design is that of a free form fern branch. Very pretty. Size is appx. 2-1/2" in length. It is two dimensional and hand crafted. The hallmark or back stamp on back of the brooch reads 18 (Arch symbol) K and under the stamp written in script appears to be France. I can share a photo if anyone wishes to see it.
Any further information would be great for me too.