Up until the fifties, a colourless or nearly colourless gem diamond was by definition a natural one. In the eighties, the first laboratory-grown gem quality diamonds appeared on the market. The arrival of these synthetic stones brought about enormous challenges for scientists and researchers. They embarked upon an intensive search for new techniques to identify the true nature of a diamond: natural, treated or laboratory-grown. What is a synthetic or lab grown diamond? Why is ‘CVD’ such a hot topic? How many synthetic diamonds are produced? How can I recognize a synthetic diamond? Can a synthetic diamond be blue? In this 2-day workshop we will discuss the synthesis methods and discuss the characteristics of synthetic stones.