1235 Brooch with Prussian 20 Mark coin and diamonds Germany 1970s. Yellow gold 14k and gold 900. Round, smooth frame, set with four swiss-cut diamonds weighing in total 0,16 carats VS, wesselton, centrally set with a 20 Mark coin, German Empire, Prussia, 1888, profile Frederick III, reverse crowned imperial eagle. Hallmark. Diam. 3,7 cm. 15,2 g.