An exquisite French Art Deco onyx diamond and black enamel jabot pin set in platinum. The head of the jabot is a large domed panel of hand polished onyx with a transitional round brilliant cut diamond collet set to the centre in mille grain platinum. A tapering panel of platinum channel and grain set with old mine cut and transitional brilliant cut diamonds runs down towards the pin from the onyx disc. This tapering panel is shouldered with Oriental style black enamel ornamentations. The tail of the jabot pin is a straight panel of platinum tapered to the end, channel and grain set with transitional and eight-cut diamonds and embellished with black enamel ornamentation. Unusually the twist to release pin mechanism is located behind the head of the jabot not the tail making it easier to put on. With an incredibly engineered platinum sub frame and pin lock mechanism. Estimated central diamond weight: 0.46cts. Estimated total remaining diamond weight: 0.41cts. Assessed diamond colour: H. Assessed diamond clarity: VS-SI.