A sapphire and diamond ring, late 18th century composite

A sapphire and diamond ring, late 18th century composite, set with a cabochon sapphire within diamond foliate shoulders in a closed-back silver and gold setting, size I, case

Accompanied by report number 313853/20064435 dated 31st October 2023 from Anchor Cert stating that the Oval cabochon blue sapphire measuring 12.5 x 9.4mm is of Sri Lankan (Ceylon) origin, with no evidence of heat treatment