This could only be Vrba, with the huge glass amethyst stones, the molded glass, and the margarita stones. The focal pint is the center square with paved rhinestones in pink, green, blue, red and orange, all prong or bezel set. The backing is the very dark and shiny metal that he used. 3" by 3" with a sturdy safety clasp. Not signed, but I have shown a photo of another amethyst brooch by Vrba. Excellent vintage condition.