Although this example dates to the 1960s, boule rings were very much in fashion in the 1930s with many designers offering their interpretations, such as Belperron, Van Cleef & Arpels and Cartier.
Bombé diamond and lapis lazuli ring by Cartier, Paris, circa 1960
We have chosen this elegant and classical half-and-half boule ring by Cartier for its somewhat unusual combination of diamonds with richly coloured lapis lazuli, carved with a fluted decoration to match the reeded shank.
The Duchess of Windsor was instrumental in establishing the vogue and owned two half-and-half boule rings by Cartier, one set with rubies and sapphires, made in 1937, and the other, set with turquoises and sapphires, dated around 1950, both showing below.
A ring of bombé form composed of half fluted lapis and half pavé-set diamonds; mounted in platinum, with French assay marks
Diamonds, total weighing approximately 2.5 carats
Marks: Cartier Paris 017207
Dimensions: 3/4 x 1 x 1 1/8 inches / 1.9 x 2.5 x 2.9cm
Ring size: 5 1/4
cf. Coleno, Nadine. Amazing Cartier: Jewelry Design since 1937. Paris: Flammarion, 2009, p.164