The composition of the stone affects the sharpness of the blade (a finer grain, usually, though not always, produces sharper blades), as does the composition of the blade (some metals take and keep an edge better than others). For example, Western kitchen knives are usually made of softer steel and take an edge angle of 20–22°, while East Asian kitchen knives are traditionally of harder steel and take an edge angle of 15–18°. The Western-style kitchen knives are generally in the range of 52–58 on the Rockwell scale, which denotes the relative hardness of a material.
Though "whetstone" is often mistaken as a reference to the water sometimes used to lubricate such stones, the term is based on the word "whet", which means to sharpen a blade, not on the word "wet". The verb nowadays usually used to describe the process of using a sharpening stone is to sharpen, but the older term to whet is still sometimes used. The term to stone is so rare in this sense that it is no longer mentioned in for example the Oxford Living Dictionaries. One of the most common mistaken idioms in English involves the phrase "to whet your appetite", too often mistakenly written as "to wet". But to "whet" quite appropriately means "to sharpen" one's appetite, not to douse it with water.
Diamond plates are available in various plate sizes (from credit card to bench plate size) and grades of grit. A coarser grit is used to remove larger amounts of metal more rapidly, such as when forming an edge or restoring a damaged edge. A finer grit is used to remove the scratches of larger grits and to refine an edge. There are two-sided plates with each side coated with a different grit.