CHAUMET - 1920S RIVIÈRE DIAMONDS NECKLACE This necklace is set with twenty-four old-cut diamonds. They are held by knife links. Mounted in platinum. French work, Joseph Chaumet hallmark. Gross weight: 24.60 g. Length: 40 cm. Total diamond weight: approximately 22 carats. Case J. Chaumet. Provenance: The jewellery box of a great French aristocratic family, this river of diamonds was part of the wedding basket of the grandmother of the current owners. A diamond and platinum necklace by Chaumet, circa 1920. French assay mark, Joseph Chaumet maker's mark. Gross weight : 24,60 gr. Lenght : 40 cm. Total diamond weight : 22 carats approx. J. Chaumet box.