Onyx and diamond double pendant necklace

The necklace with a singular row of old brilliant cut diamonds box collet millegrain set, with four onyx crossover motifs set between, the double drop pendant centred by a large millegrain set round brilliant cut diamond, surrounded by calibre cut onyx curves to form stylised bow, from which is suspended two further round brilliant cut diamonds, the rest of the bow formed by two varied length drops, further suspending two diamond kite shaped drops, all mounted in platinum, French workshop mark to clasp
Length from clasp to end of longest drop: 24cm / 9 1/2''

Width of onyx section: 0.5cm
Weight: 35g