Technically, the name whetstone can be applied to any form of sharpening stone, regardless of what cutting fluid is typically used with it. However because whet sounds like wet, many hear the word and assume that it refers to a stone that is used wet with water. Actually, water stones, oil stones diamond stones and ceramic stones are all forms of whetstones. So, while all water stones are whetstones, not all whetstones are water stones.
Over the course of two days I re-sharpened nearly a dozen old blades, including removing the secondary bevel on an old stainless Ontario saber-grind Navy diver's knife, convexing the edge on flat ground 1095 Schrade 55 that also came with a secondary bevel, and fixing a broken tip on an old Kershaw folder. These stones made quick work of the Schrade and Kershaw. Both had completely new edge geometry within 30 minutes apiece. The Kershaw looked like-new, as if the tip had never broken. And the Schrade cut much better than it's secondary bevel would previously allow, regardless of how sharp I got it with a ceramic rod and strops. The Ontario took a little more work, as it had been abused a little the last time I'd held it, over 25 years ago and was as dull as a case knife - one of the reasons I decided to go ahead and do a full saber grind - well, a slightly convexed saber, I suppose would be more accurate. But within under an hour of using the two stones and a couple leather strops (one with black compound, another with green), the Ontario was shaving sharp again too.
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.
Unfortunately, the arrays of modern whetstone can be bewildering to the inexperienced sharpeners that so often times many of them end up with a crap or wrong decision on stone type for their utensils. The most difficult to determine is whether the whetstone is fake or fabricated with low quality of materials. To avoid this you can only go for the reliable brand of a whetstone.
My first set of sharpening stones so I have nothing to compare them to. For $50, though, great price to get into the world of sharpening. Stones are great and easy to use. Was able to put hair shaving edges on knives. Took a couple of knives to feel comfortable and better with the process and how to sharpen, but the stones you get work great. Here's the secret though. Get the green leather stoping block as well. As great as the stone are, I have found that stroping the knife after the fact is what really brings out that razor edge. And after using the knife, stroping it again, will restore and keep it razor sharp. Hope you enjoy it as much as I am.