Sapphire and diamond ring, France, 1920s. Stone cutting was revolutionised during the opening decades of the 20^th century - alongside the new ‘baguette’ cut for diamonds, jewellers also began to cut coloured stones in new and inventive ways. The sapphires in this ring have each been facetted to tessellate within the rectangular setting, and around the two central diamonds. Known as a ‘calibré-cut’, cutting each of these to fit the mount is a very intricate and labour-intensive process, practised by only the most skilful jewellers of this period. With this artful arrangement of calibre-cut sapphires and millegrain-set diamonds, this beautifully handmade ring is a tour-de-force of the jeweller’s art.