Finding ways to routinely and reliably produce larger near-colorless and colorless single-crystal diamond needed for a variety of applications in science and technology is a major challenge. Meng et al. (pp. 101–104) have refined microwave plasma assisted chemical vapor deposition (MPCVD) techniques to produce large, high-purity single crystal diamond anvils. Specifically multicarat single crystal diamond has been produced at high growth rate without annealing (around 50 μm/h) with low impurities content. The example shown in the image is a 2.4 carat colorless CVD diamond anvil which was cut from a crystal 13.5 carat block. UV—visible absorption, Raman/photoluminesence spectroscopy, cathodolunminesence, and confocal Raman imaging are used to characterize the diamond. The measurements show that the material has high optical quality and clarity without layers. The large intensity ratio of the second-order Raman peak to the fluorescence background is essential for high-pressure optical windows. The origin of the residual color is also examined.