Blemish is a clarity characteristic that occurs on the surface of a diamond. It is important to distinguish the difference between inclusions and blemishes as inclusions refer to imperfections inside the stone only. Some blemishes could be inherent to the rough diamond crystal itself and may very well be the result of natural causes. However, a blemish can also be the result of a non-natural cause. Seeing as diamonds can only be scratched by diamonds and diamonds are polished with diamond material, a blemish can also occur during the actual polishing process or even when two diamond jewelry pieces are stored together.