VS1 - VS2: You can see flaws with a 10X microscope, but it takes a long time (more than about 10 seconds). SI1 - SI2: You can see flaws with a 10X microscope. I1 - I3: You can see flaws with the naked eye. Consider avoiding I2-I3 diamonds. REMEMBER: For grades IF through SI, a diamond's clarity grade has an impact on the diamond's value, not on the unmagnified diamond's appearance. While Flawless diamonds are the rarest, a diamond does not have to be flawless to be stunning.