Beautiful Unique Antique 18K Gold Mounted Carved Shell Cameo Leda and the Swan Mythological Pendant Brooch. The brooch may be worn as a brooch or with a chain through the ring on the back as a necklace. The quality and the detail of this gorgeous cameo is superb. The pin holder on the back is marked 18K. It measures 2-1/8 inches high and 1-1/2+ inch wide. The condition is excellent. It weighs 14.1 grams.