Sapphire and diamond ring, early 20th century. The square setting of this ring is set with old European-cut diamonds surrounding a beautifully proportioned cushion-shaped sapphire in a cornflower blue hue. The borders are dotted using the 'millegrain' technique, which jewellers developed at the turn of the 20th century in order to soften the metallic sheen of the new platinum settings. As this ring shows, when combined with the brilliance of the diamonds, the effect is a soft white shimmer – the perfect counterbalance to the cool blues of the central stone. The shank is stamped '18ct' for 18 carat gold.