Signed WMCA Art Deco two part Brooch with crystal rhinestones

This is a unique Art Deco brooch dating to the 1930's to 1940's. It is signed WMCA for white metal casters association that was founded in 1930 in NY,NY. Little is known of this association. It consists of two parts. The upper piece is rectangular with crystal baguette stones flanked by tiny paste stones. The bottom portion is a round disk with pave set crystal stones. The stones are bright with a lot of sparkle. The piece is white metal and has a C clasp closure. Size is 1 1/2 inches in width by 3 inches in length.