I want to sell my mother's ring that I inherited. It is an 18 karat white gold diamond cluster ring containing one fancy intense yellow natural colored diamond. GIA Certificate 1 transparent yellow round brilliant cut stone measuring approx. 5.03 - 5.08 x 3.16 mm., wt. 0.49ct. Diamond, fancy intense yellow natural color. SI 2 Insurance Appraisal $7,058.00. I know it is probably appraised higher than actual worth. What should I be asking for this ring. Is there a website that would be able to give value? Thanks