Lady's 18K Yellow Gold Invisibly Set Sapphire & Diamond Ring. Ring Size: 6 1/2 Contains: 14 Invisibly Set Fancy Square Cut Natural Sapphires. Weight: 1.50cttw, Color: Blue, Clarity: Transparent-LI. 18 Round Brilliant Cut Natural Diamonds. Weight: 0.60cttw, Color: G-H, Clarity: VS1/VS2. From the stock of a deceased upscale mid-western jeweler comes a spectacular 18K Yellow Gold diamond and sapphire cocktail ring featuring fourteen invisibly set sapphires. Invisibly setting is a very laborous process invented by Van Cleef and Arpels.