In recent years, some whetstone manufacturers have started producing ceramic whetstones made from hard, ceramic, powders that are mixed with Aluminum Oxide and then sintered to form a solid. But, rather than using oil or water to lubricate the whetstone, ceramic whetstones are meant to be used without lubrication and thus, they provide a significant advantage for chefs who need to keep their knives sharp but, who do not have either the room or time for using a bench water stone. Thus, they are commonly available as either bench stones, pocket stones, round rods, or triangular rods.
Sharpal 178N TRANSFORMAN 3-In-1 Diamond Round and Tapered Sharpal 178N TRANSFORMAN 3-In-1 Diamond Round and Tapered Rod Sharpener makes it easy to sharpen all kinds of knives including those with serrations gut hooks fishhooks and pointed tools. Industrial monocrystalline diamond is electroplated in nickel onto a steel base. Sharpen dry. No messy oil needed. Fine 600 grit (25 ...  More + Product Details Close
Diamond hones are made from very small, industrial grade, diamonds adhered to the face of a metal or plastic plate. Also, because Diamonds are so much harder than any of the other sharpening materials, they tend to cut very fast and last much longer than the other whetstone materials. But, they are also often more expensive to purchase. In addition, Diamond Stones generally consist of three different styles consisting of a solid metal plate coated with an adhesive and diamond dust with holes in the plate to allow the swarf to escape, a solid plate without holes for sharpening tools with corners that might catch in the holes, and a plastic plate with islands of exposed plastic interspersed with the adhesive and diamond dust to act as a lubricant.
I had wanted a pair of sharpening stones for a while, so was enthused to get this last week. I watched a bunch of YouTube videos on how to use them and a deburring strop I also bought and wow, my kitchen and pocket knives are now wicked sharp. Pro tip: if you post anything about it on social media, family and friends will almost surely volunteer their knives for more practice...
The unique three stone system features a 6" medium Arkansas, 6" fine Arkansas and 6" coarse synthetic stone mounted on a molded plastic triangle with handles on the end for easy stone selection. The sturdy molded plastic base has non-skid rubber feet for safety, a V-shaped trough to catch oil drippings and easy-to- read stone identification markings.
While it may still feel like there is a lot to choose from, you don’t need a lot of of stones, you just a several good varieties to choose from. To summarize I will indicate below what my favourite stones are in each grit. Yes you can mix up the brands when sharpening but my recommendation is to buy a combination of 2-3 stones of the same brand and go from there.
Both Belgian Blue and Vielsalm Coticule are ancient stone layers found in the Belgian Ardenne Mountains with characteristics similar to both Novaculite and Siliciclastic sedimentary stone in that it is a metamorphic stone consisting of both gray and yellow volcanic ash mixed with tiny Spessartite Garnet crystals suspended in a clay matrix. However, due to its geology, both types of stone occur only in vertical seams sandwiched between two thick layers of bluish-purple slate and thus, they must be meticulously extracted mostly by hand. However, this type of extraction process is both very time-consuming and very labor-intensive and, quarrymen can only extract the stone for a few months each year due to inclement weather conditions. Consequently, both Belgium Blue and Coticule whetstones tend to be somewhat expensive.
Diamond whetstones, like the DMT Diamond Whetstone, are made out of industrial type diamonds which create a long-lasting hard, coarse and flat surface. A diamond whetstone is an excellent choice for when you are outdoors as you can use it dry or with a lubricant. It can take some time getting used to and the larger sized stone may not be ideal for working with small knives or cutting tools.
When the stone is intended for use on a flat surface, it is called a Bench Stone. On the other hand, small, portable, hand-held stones are referred to as Pocket Stones. Also, because Pocket Stones are smaller than Bench Stones, they are more easily transported but, they also present difficulty in maintaining a consistent angle and even pressure when attempting to sharpen longer blades. Consequently, Bench Stones are commonly used at home or in camp whereas, Pocket Stones are generally reserved for honing an edge in the field.
Once you’ve decided to start sharpening your kitchen knives with a sharpening stone, you’ll need to take the necessary steps to actually get going. These steps include finding and buying the best sharpening stone for use at home, learning the basic technique involved in doing the sharpening, and then practicing enough times to get it right. (For the sake of the knives, we don’t recommend using your best kitchen knives for practice!)

For this type of hand held manual sharpener the 463 does an extraordinary job thanks mostly to the diamond abrasive wheels. You get an edge that’s both razor sharp and burr-free, as if you spent an hour working the edge on an oil stone. If people make a mistake with the 463 it’s that they assume more pressure is needed than actually is. Keep in mind though that it really shines on serrated and straight edged, double bevel Asian-style knives.
Medium Grit Stones: The number range here is from 1000 to 3000, with the latter being the basic, go-to sharpening stone. If your knives have lost their edge and need a good sharpen, then this is the grit you should start with. Don’t use it too often or the knife wears down rapidly. If you like to sharpen regularly, then the 2000 and 3000 grit are the ideal choice as they are less coarse, but please remember they are designed for sharpening and not maintaining the edge.
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.
You need to adjust your fingers as you move the knife back and forth. Because sharpening takes place under your fingers, start with them at the tip and, as you pull the knife back toward you, release pressure completely and pause. Then, shift your fingers just a little down the blade toward the heel. This finger dance is critical and takes time getting used to.
The word “Novaculite” is derived from the Latin word “novacula”, which means “razor stone” and is essentially a metamorphic, recrystallized, variety of Chert composed mostly of microcrystalline quartz that is found in the found in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift of  Deposited in the Devonian Period and the early Mississippian Subperiod some 410 to 325 million years ago and subjected to uplift and folding during the Ouachita orogeny of the Atokan Epoch (early Pennsylvanian Subperiod), Novaculite is a very tough stone that is resistant to erosion and thus, the various layers of Novaculite stand out as ridges in the Ouachita Mountains. Thus, due to both its availability and its composition, it has been mined since ancient times for use as arrowheads and spear heads as well as in more modern times for use as sharpening stones.
Low Grit Stones: A sharpening stone with grit number less than a 1000 is generally used for knives and tools that are damaged. If your blade has any nicks or chips in the blade, the stones will take care of them in a jiffy! They usually have a coarse side for nicks and chips, with the other side for general sharpening. Even if the knife’s edge has become totally blunt, the stone will re-sharpen it perfectly.
I've used ceramic rods, diamond plates, and leather strops for our sharpening needs. And, like most, I've tried a dozen little gimmicky sharpeners that, while some work, those that do often remove way too much material from the edge, making your blade wear down faster. I've also used oil stones, grinders and buffers for less meticulous sharpening of axes and such. These two stones from Unimi (600/1000 and 2000/6000) served as my introduction to whetstone sharpening. And I must say I like it. Though, I'm not sure of the need for investing in more expensive stones.
Once the burr is removed, it's time to test the sharpness with paper. Hold a piece of newspaper at about 45°, with a bit of tension, and slash lightly with each point of the blade. If it cuts through easily, your knife's sharp. Warner speedily lacerated his newspaper, but I of course struggled. There is an element of technique involved, he reassured me. 
Some of the videos I watched suggested soaking the stone for 12-15 minutes prior to use. One suggested using vegetable oil on the surface versus water/soaking (I used water and presoaking it for 15-minutes). So instead of a simple 'out-of-the-box-and-use' approach, it required a bit of research before sharpening a knife. Otherwise I would have given this product a 5-star rating.