Sterling Silver 4mm Round Sapphire Stud Earrings Sapphires measure 4mm .925 sterling silver settings and traditional push backs Dark blue sapphires Sapphires may be heat treated or oiled to enhance color All our diamond suppliers confirm that they comply with the Kimberley Process to ensure that their diamonds are conflict free. Sapphires measure 4mm .925 sterling silver settings and traditional push backs Dark blue sapphires Sapphires may be heat treated or oiled to enhance color