How much is my ring worth? any ideas? it was about $500 when i bought from sears in 2008.?

one 14k yellow gold mounting(ring),weighing in total 1.5 DWT.,stamped 14k F.26 with logo,containing one natural diamond (set in white gold), round brill cut, measuring: 4.07-4.12 x 2.46 MM. weight 0.26 carat, color: colorless(F), clarity SI(2), polish: good, symmetry: good.