Is the diamond used as cutting edge a natural diamond?

Basically a synthetic diamond is used. In case of natural diamond, the quality is not homogenous, while there exists one with an excellent quality, there exists one with defect containing impurities or crack. On the other hand, the quality of synthetic diamond is homogenous in quality making it suitable for making cutting tools, therefore, synthetic diamond is generally used, except for a limited kinds of turning tool where a natural one is used.