While there is a wide variety of man-made sharpening products on the market that work reasonably well, natural quarried benchstones hold a special fascination for many of us. Rare Japanese waterstones actually sell for hundreds of dollars to aficionados, and American Arkansas stones have an equal number of fans. Some of the lesser-known natural stones are the coticule hones quarried since Roman times in Belgium. These stones have the advantage of being based on garnet crystals rather than the much softer quartz/silica abrasives found in most other mined stones. Belgium stones come in two general varieties, “blue” and the much more rare “yellow.” Recently, I noticed that Boker Knives was carrying both types in the sharpening supply section of their catalog, so I ordered a pair.

Blue Versus Yellow

Having discussed each type of stone at a trade show in Germany with the Belgium company that actually quarries all of corticule hones, I know that primary difference between the two is that the yellow simply contains a higher percentage of garnet crystals in the base material, a type of shale. There is no real distinction between grit fineness; both are around 2,000 to 3,000 on the Japanese scale. Where they differ is in their speed of cutting—more crystals means faster steel removal. Offsetting that is the fact it is much easier to quarry larger-size hones from the blue deposits than it is from the yellow layers. Naturally, the yellow hones tend to sell at a premium over the more common blue stones. Boker’s blue Belgian is 8-by-2.5-by-0.75-inches in size and has a suggested retail price of $99.95. The smaller yellow stone is 6.8-by-1.5-0.75-inches in size and, as one would expect, has a bit higher in price—$139.95. Both stones come in a wood storage boxes to prevent damage when not in use.

One of the major advantages of the Belgium stones over most of the traditional Japanese natural waterstones is that they are what serious sharpeners call “splash and go.” Both types use water rather than oil for a surface lubricant, but where a Japanese stone requires a long soak before use, all a Belgium stone needs is a little bit of water poured over the top of it. Like the Japanese stones, the coticule hones form on the stone surface a “slurry,” or a mud, made of the sharpener’s base material and the particles of its abrasive content. The slurry helps both sharpen the edge and polish the surface of the blade’s bevels during use. Unlike most man-made and Arkansas stones, the surface of a Belgium doesn’t clog with steel filings and worn abrasives. Just give it a quick rinse after use, and it is ready for the next sharpening session.

Razor Hones

Back in the days when most men shaved with a straight razor, blue and yellow Belgium stones were often referred to as “Belgium razor hones.” Obviously, anything suitable for bringing a razor to shaving-level sharpness is of relatively fine grit. Despite what the folks who quarry these stones claim, I have always found them to be relatively slow at dealing with very dull edges. This isn’t to say they won’t eventually bring the edge back; it just takes awhile. My answer is to do any heavy metal removal with a silicon-carbide, aluminum-oxide or diamond-surfaced sharpener, and then finish the edge on the Boker Belgiums.

Ideally, you touch the edge up on the coticule benchstone on a regular basis and only use coarser abrasives when the primary bevels require thinning. That might vary from once a month on a knife in daily use to almost never on a hunting blade that processes a single deer per year. I keep a blue stone next to our sink in the kitchen and use it frequently for quick touch-ups on both food prep knives and my everyday carry folders. The Boker blue stone will bring most un-abused edges back to shaving sharp in about 60 seconds.

With its smaller size, the Boker yellow stone works best on shorter blades like those found on the average folder and fixed blade hunter. You can also hone your wood-working tools equally well, if that happens to be a past time of yours, and, of course, the stones still do the job on a straight razor if you are into the “retro” shaving movement. Surprisingly, a lot of people are these days.
It really doesn’t matter what miracle alloy a knife is made from if its blade is not kept sharp. These stones may seem a little on the expensive side, but they will provide for you a lifetime of finely honed cutting edges. Doesn’t the edge on your carefully selected tactical companion deserve equal attention?

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For the complete article please refer to Tactical Knives July 2013.

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