Polycrystalline diamond (PCD) is a man-made diamond material used for drilling and machining operations. Its vastly superior hardness to any other material allows it to cut through challenging materials such as rock, high-strength metals and carbon fibre composites whilst itself wearing away very slowly. However, at high temperature, it suffers from mechanical breakdown as the heat causes some of the diamond to transform to graphite aided by cobalt metal which is left over within the PCD from manufacturing. This experiment will aim to accurately measure the stresses that are put on the remaining diamond when some of it transforms to graphite as it is heated and how this varies if you dissolve away the remaining cobalt with acid. The difference in stress between the horizontal and vertical directions in PCD will also be measured as it has previously been shown to be greater than zero.