by moommen » Jul 4, 2017 Had the pleasure of purchasing a fantastic diamond through Martin Sheffield at USA Certified Diamonds. I have heard stories of people spending months searching for the perfect diamond but fortunately Martin has a great eye for amazing stones and was able to locate mine within a few days. The entire process was extremely smooth. Once he located the perfect stone he took care of the process and included the appraisal, which most places charge $100 for. His passion and knowledge come through in the diamonds he recommends my fiancee could not be happier.