'Rainbow' necklace with colored stones, 1 brilliant-cut diamond of 0.5 ct

Necklace 'Rainbow' with trapeze-cut faceted tourmalines, peridot, citrine, 1 brilliant-cut diamond ca. 0.5 ct and small brilliant-cut diamonds totalling ca. 0.3 ct, ca. RW (G)/VS-SI, 18K yellow gold, 64.6 g, L: 50 cm, late 20th century, good condition, with jewellers certificate, after reworking not exactly matching anymore and add. diamond certificate.