Marcus & Co. Art Nouveau brooch, “Tibula” shaped 18k yellow gold brooch set with three natural pearls, the natural center button pearl approx. 10 mm in diameter (G.I.A. certificate, 3 natural freshwater pearls, weight 24.90 grams, measurement range from 5.46 to 12.26mm), 16 sugarloaf cabochon sapphires, the two large and high dome middle sapphires with a purple hue, 20 pave set round diamonds all surrounded with clear plique-a-jour further trapped with platinum flakes, signed c. 1897