Plate brooch in platinum (950) stylizing a knot with openwork geometric decoration, entirely set with old-cut, baguette-cut or eight-eighths-cut diamonds in beaded, closed or rail settings, and centered with a larger half-cut diamond in closed setting. Pin in white gold (750). Art Deco period, circa 1925. Gross weight: 16 g. - Size: 5 x 2.6 cm. A few chips.