Vintage marcasite Leaf brooch

Stamped Sterling Silver on the reverse. True vintage. 1940s or 50s. Gorgeous. Looks to me like a BIRKS piece, but I can't find the B logo stamp. This piece is part of a collection of vintage jewelry which has been in storage since the '90s. All functions are functional unless otherwise noted. All are in an unpolished condition, precisely as found. Please look closely at the images and / or video to note the exact condition. For sizing, see photos on the green grid. It's ruled in cm. Dotted lines show the 0.5 cm marks. (None come with a dedicated jewel box unless one is shown in the photos.) Please feel free to pick a few items you like, and send me an offer. I'd love to bundle a very nice deal for you!