There are many names for conventional laboratory grown diamonds: 'man-made', 'created', 'above-ground'’ or 'synthetic'. They are created by replicating similar high-pressure, high-temperature conditions as mined diamonds. A selected diamond 'seed' experiences these conditions in a lab, crystallising into a rough lab-grown diamond after several weeks. The rough jewel is then cut and polished, resulting in a stone with the same chemical and optical properties as mined diamonds.