Diamond Price Estimator is a free online tool that helps calculate cost of loose diamonds for when you sell or buy. This is the most accurate and up-to date calculator of TRUE value of GIA certified or uncertified stones. The calculation is based on Rapaport Diamond Price list (Rap sheet) which is used by 99% of jewelers world-wide. Use this calculator and attached copy of RAP price list when buying your diamond from independent jewelers to get best price. Also read a comprehensive guide on how to bargain with jewelers, and why you should never buy jewelry from mall-based stores such as Zales, Kay, Ross-Simmons, Tiffany and others.