Art Deco Platinum Diamond Brooch Black Onyx Ruby 1920s Vintage JewelryA striking Art Deco platinum and diamond brooch, featuring black onyx and ruby; circa 1920s. The broochs centerpiece features a trophy like vase set with old European and single cut diamonds, accented by a row of vivid rubies. A backdrop for the vase is a black onyx and platinum checkerboard pattern. The rectangular platinum frame is fully set with diamonds. Lantern like motifs complete the background, emphasizing the broochs architectural influence.