Antique Sapphire and Diamond Ring For Sale at 1stDibs antique diamond Antique Sapphire and Diamond Ring For Sale at 1stDibs antique diamond Antique Sapphire and Diamond Ring For Sale at 1stDibs antique diamond Antique 18ct Sapphire and Diamond Ring Antique Sapphire and Diamond Ring in 18k Gold The Antiques Room. An antique ring from the early years of the 20th century. Centre stone 5mm diameter (0. 50 carats) Colour H j, clarity Si. Each side a mid colour blue sapphire 4mm diameter. Each end a matching diamond, 3. 7mm (0. 18 0. 20 carats) All diamonds old brilliant cut. Head hand carved 17x6mm, depth 4mm, weight 3. 5grams. Tests as 18 carat gold, no hallmarks required for this period. Size Q, we can resize free of charge.