A sapphire and diamond-set cluster ring, the oval mixed-cut sapphire (10.5mm x 7.7mm x 5.4mm) within

A sapphire and diamond-set cluster ring, the oval mixed-cut sapphire (10.5mm x 7.7mm x 5.4mm) within a border of ten brilliant-cut diamonds the plain tapering shank stamped '18CT PLAT', ring size P (4.5g)