An impressive boulder opal and diamond pendant necklace, featuring a 27.5 x 6 - 25 mm triangular shape fine boulder opal with rich multi colour range (approx. 25.83ct), in an 18ct gold and platinum leaf form frame set with 36 round brilliant cut diamonds, on a twisted helix platinum chain with bolt ring clasp, pendant size 52 x 32 mm, TDW = 0.56ct, chain length 45 cm, wt. 26.74g, with cert.