An Art Deco Brooch: Costume Jewelry

One of my soft spots, the favorite brooch in my collection. Art Deco/Nouveau ornamentation, aquamarine glass... With a secret catch.
I'm not sure about the origin, maybe Bohemia. Who cares? It is wonderful. I won't check "need help identifying", but if someone can tell me where it comes from, I'll be a bit happier.

Thank you for reading this.