What kind of stone is used for knife sharpening most often?

Whetstones are the most commonly used stones for sharpening knives. They are made of various abrasive materials, such as silicon carbide, aluminum oxide, or natural stones like Arkansas stone or Japanese water stones. These stones are available in different grits, which determine the coarseness or fineness of the stone, allowing users to achieve different levels of sharpness depending on the need.