An amethyst and diamond brooch / pendant, 1970s, of abstract design, the sculpted gold plaque composed of three graduated polished and openwork panels, accented by single-cut diamond detail, the octagonal amethyst weighing approximately 15.00 carats, diamonds approximately 0.34 carat total, mounted in 18 carat yellow gold, gross weight 29.1 grams, width 4.0 cm