# Belgian coticule natural stone



## Benuser (Apr 26, 2017)

Any experience here with using it with kitchen knives? Got a little piece of it, and it's a relatively fast fine stone, and a very fast deburrer. But have only tried with carbons so far.


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## Noodle Soup (Apr 26, 2017)

I keep one by the kitchen sink as a quick splash and go stone for touch ups when I'm not interested in going the full waterstone soak route.


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## LifeByA1000Cuts (Apr 27, 2017)

@Benuser have both the blue and yellow - blue is excellent splash and go carbon touchup stone indeed, the yellow is a good followup 

Especially with the blue, it was a learning curve to not scratch them.

The blue is fast enough to do post-sharpening, in kitchen corrections (eg "damn, missed a spot on the belly and already packed the sharpening gear" situations).

Works on stainless (tested with everything from cheap 420 to ZDP) too, but won't give you the sort of polish the SS 5000 would... 

They are reputed not to easily raise burrs - which appears true, and is a huge boon in touchup/fixup stones.


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## Benuser (Apr 27, 2017)

Interesting, have only tried the yellow one. It's my understanding that the yellow one are just faster as they contain more abrasive particles.


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## tsuriru (Apr 27, 2017)

I use coticules sometimes. I have a few of them. All coticule are about 1000 grit according to Bart on what was once www.coticule.be huge mine of information on these stones there. The thing is, because this 1000 grit kernel is a serpentite embedded in a matrix with compressed clay it does behave differently to JNAT that requires a different approach to slurry and it's dilution.

After thought: Regarding the chrystal content in each respective color, keep the following in mind: These are stones that come from SEVERAL veins with somewhat simillar traits regarding content. Blue is about 30-35% yellows go as high as 40-45%. Im not sure that higher chrystal content = faster stone. In fact, Belgian blue stone is probably one of the most under-appreciated stones. But as with all things natural short of going to Belgium and testing some material out in the mine, it is a bit of a crapshoot as to how WOW the stone you get will in fact be.


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## LifeByA1000Cuts (Apr 27, 2017)

Usually, the yellow are rated as 8000-10000 (10000, and handles up to 70HRC, i what I have been given by one of the official sellers on their trade show stand ... I'll probably be remembered as the puzzled guy trying to refine a knife that was lying around there for demo, forgetting that outdoor knives don't have 12dps-ish bevels usually  ).

The consensus on the blue seems to be "around 5000".


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## LifeByA1000Cuts (Apr 27, 2017)

@tsuriru AH, there is an obscure rumour that these are 1000 *if used with slurry*, so opposite to JNAT behaviour. Given that my blue seems really rather sensitive to knocking big pieces loose if you bite into the stone (feels as if you got sand on your stone), I guess even 40 with slurry would be possible


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## tsuriru (Apr 28, 2017)

Bart worked with some guy that was doing electron microscopy at the time and came up with 1000 grit serpentites....he claimed that the 8000-10000 was a marketing hype. I tend to agree with him. But it does not make these stones any lesser. Then again, they may have got it wrong...

Look here: http://www.coticule.be/the-cafeteria/message/14592.html and here http://www.coticule.be/faq-reader/i...-to-a-coticule-40a-story-about-garnets41.html


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## LifeByA1000Cuts (Apr 28, 2017)

Fact is, these don't eat metal like a 1000, and people have been honing razors on them for ages (slurry first, then clear water seems to be the common way), which certainly is not a common use of 1000 grit hones  Talk about bald faced lies...

Always remember that every stone is also a coarse stone - at a grit determined by the stone size....


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## Sharpchef (Apr 28, 2017)

I love coticules all the way..... But mainly for razor sharpening....

A good coticule (old ones, hard fast and fine!) kill any Jnat in terms of speed.... There are so may variations of them you can`t even imagine..... The problem for kitchen knife sharpening is the following:

They make a smooth shave! nearly no risk to cut into face, but this is what we need in kitchen, cutting skin! of maybe tomatoes peppers pork skin etc......

BBW`s are good also especially for prefinish stage, because of the extra large round garnets (up to 25my) sitting in the stone matrix, and cut really fine because of their round shape... So the best sharpeners i know use them after! 10k hone! and proceed with even finer abbrasives like well broken in Black Arkansas or jasper.....

Greets Sebstian.


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## Benuser (Apr 29, 2017)

Thanks a lot, guys! Most helpful.


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## LifeByA1000Cuts (Apr 29, 2017)

An AS knife of mine that had big problems with initial sharpness loss, going into the "durable but hardly arm hair capable" phase quickly, seems to have left that problem behind after it was last touched up on BBW->Coti. I wonder if that is a coincidence or if the coti is just that well matched to AS?


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## Benuser (Apr 29, 2017)

With AS, make sure to start with a rather coarse stone, just for a few strokes to raise a burr. Refine as much as you like, but the coarse stone will benefit a lot to edge stability. Best results with ending with a very conservative edge -- and thinness behind it.


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## LifeByA1000Cuts (Apr 29, 2017)

@Benuser are you saying "treat it as a high alloy steel, like a stainless but without a refinement ceiling, but not like shirogami?"


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## Benuser (Apr 29, 2017)

Has to do with the tungsten carbides, I guess. Expect no theory here, just a little experience. Treat it as another carbon but start with a few coarse strokes. With most stainless I rarely suggest any refinement, except for AEB-L. And with good AS I've seen a crazy edge stability with a rather conservative edge.


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## Benuser (Apr 29, 2017)

But haven't tried yellow coticule or BBW with AS, yet.


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## LifeByA1000Cuts (Apr 29, 2017)

I did notice that plain 12dps will do great on hard shirogami and lousy on AS  Wonder on which side of the equation V2 is (I have no V2 knife but everybody is saying they're great)?


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## Benuser (Apr 29, 2017)

I only know the V2C with Masahiro in their Virgin Carbons, and it indeed holds an incredible acute edge fairly well. Not that you should aim for that IMO: better keep it very thin behind the edge, and benefit from edge retention.


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## Benuser (Apr 29, 2017)

It's really a misunderstanding to look for extremely low sharpening angles. Especially with carbons you may reach a very high level of sharpness with rather obtuse angles thanks to the fine grain structure.
And in daily life thinness behind the edge is much more decisive, except for jig system victims.


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## LifeByA1000Cuts (Apr 29, 2017)

Counterintuitive - I'd expect an obtuse but sharp apex to need teeth more than something acute that has "pressure focusing"* on its side?

*for lack of knowing the correct term - I mean, a pin will easily penetrate tomato skin because of being so acute - would a polished nail?


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## Benuser (Apr 29, 2017)

A well polished obtuse carbon edge will cut a tomato skin. Or do you think Escoffier couldn't cut a tomato?


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## Benuser (May 13, 2017)

Just made the comparison between coticule and BBW. My BBW crazy hard, achieving almost the same end result as a coticule, but much slower. For final deburring the coticule seems more appropriate, for rougher work as well, not using water but...saliva. Spick so to say. Leaves with the coticule an aggressive thick slurry. 
Thinned with water one reaches a much more refined result.
So the use of BBW seems to be more limited, and that of the coticule very large.


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## Butters (May 22, 2017)

I love coti's. I have a few that are very hard and fine that are more suited towards razors but I have one beautiful combo stone (coti & bbw naturally joined) that is perfect for knives. It's much softer that the usual coti and has what feels like coarser garnets. It's fasts too and the only steel it has struggled on is zdp189 (a spyderco dragonfly). It leaves a toothy edge that works really well, and if I compared it to a synthetic it would perhaps be 3000 grit. My harder coti's are more like 5000+ and leave a highly polished edge, which is not my preference for most knives in the kitchen.

They are natural stones and often very different. If you talk to Maurice at Ardennes Coticule he will pick out a stone that suits knives more than razors. It's not quite as deep a rabbit hole as Jnats however the good stones are still rare & expensive...


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## LifeByA1000Cuts (Jul 27, 2017)

An interesting aspect: I was able to get a carbon (the Goko W#1) from "stropped a lot, still kind of razor-ish but like a nasty rusty razor, probably from spots too coarse to strop out" to "cuts smooth and deadly" with just the yellow coticule (and some newspaper and balsa/crox - but these alone would just give you the rusty-razor effect!) - and without raising a clear burr or having to remove one (tested the edge dry-chopping - yep, holds, that is no wire edge).

Also, seen some market knife sellers that sell small coticules with their carbon knives demonstrate very "wild", "random" sharpening technique ... now I see how that could actually work with these stones... seems there is some truth to the "faster than a normal #8000, and raises no burr" ...


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## loong (Aug 5, 2017)

Wondering how does coticule compare to Jnats?


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## Razor (Aug 6, 2017)

loong said:


> Wondering how does coticule compare to Jnats?



Coticules cutting media are garnets. Jnats are fossilized radiolaria. Coticule progression is done by dilluting the slurry that you create with a Coticule slurry stone or diamond plate. After creating the slurry which can be very fast cutting, you progressively add water and finish on plain water. It requires a lot of feel and patience. Most Coticule top out at around 8k. But the finish is nothing like an 8k synthetic. Coticules are named based on the layer from which they are mined and are judged by particle size and density. 

Jnat progressions are done using a fine and hard base stone (Awasedo) with different slurry stones (nagura) that have different cutting qualities. You progress from Botan to Mejiru, Tenjou, Koma and then Tomo Nagura (like the base stone). You could also use full size base stone versions of all those but it would be thousands of dollars. Jnat base stones and Nagura are graded on hardness, particle size and particle density. I prefer medium hard Awasedo that self slurry.


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## loong (Aug 8, 2017)

Razor said:


> Coticules cutting media are garnets. Jnats are fossilized radiolaria. Coticule progression is done by dilluting the slurry that you create with a Coticule slurry stone or diamond plate. After creating the slurry which can be very fast cutting, you progressively add water and finish on plain water. It requires a lot of feel and patience. Most Coticule top out at around 8k. But the finish is nothing like an 8k synthetic. Coticules are named based on the layer from which they are mined and are judged by particle size and density.
> 
> Jnat progressions are done using a fine and hard base stone (Awasedo) with different slurry stones (nagura) that have different cutting qualities. You progress from Botan to Mejiru, Tenjou, Koma and then Tomo Nagura (like the base stone). You could also use full size base stone versions of all those but it would be thousands of dollars. Jnat base stones and Nagura are graded on hardness, particle size and particle density. I prefer medium hard Awasedo that self slurry.



Thank you&#65281; Very insightful review!


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## Matus (Aug 8, 2017)

I am no expert on Jnats, but that is just one possible way to sharpen an edge - normally one would progress over a few natural stones most of which (or none at all) will require a nagura. What Razor described would be geared more towards, well, razors which require much finer edge than kitchen knives.


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## Razor (Aug 8, 2017)

Matus said:


> I am no expert on Jnats, but that is just one possible way to sharpen an edge - normally one would progress over a few natural stones most of which (or none at all) will require a nagura. What Razor described would be geared more towards, well, razors which require much finer edge than kitchen knives.



I just bought a Miyabi SG2 Utility. After one use cutting meat, celery and potatoes it showed chipping. Very disappointing. Even more so since the SG2 8" Chef's knife I received the previous week had a bent tip and had to be returned. Anyway, rather than pull out my 1k Chosera and remove a lot of steel, I grabbed my Nakayama Asagi and used a Botan nagura to remove the chips. I then progressed through Mejiro and even Koma. The chips were gone, the edge was mirror polished and it cut nicely. So far no new chipping has been observed. Good nagura can be very fast cutting on a kitchen knife. BTW these nagura are the same stones sword makers used and still use to polish samurai swords.


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## Benuser (Aug 8, 2017)

Chipping with brand new knives is all too common, I'm afraid. I guess it has to do with factory buffering.


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## tsuriru (Aug 8, 2017)

loong said:


> Wondering how does coticule compare to Jnats?


I often wonder the same thing about oranges and tomatos.


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## Razor (Aug 8, 2017)

tsuriru said:


> I often wonder the same thing about oranges and tomatos.



Well, they're both fruits.


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## tsuriru (Aug 8, 2017)

Razor said:


> Well, they're both fruits.



They are also both round(ish).


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## Nemo (Aug 8, 2017)

tsuriru said:


> They are also both round(ish).



And acidic


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## loong (Aug 8, 2017)

tsuriru said:


> I often wonder the same thing about oranges and tomatos.



So a Nakayama and a coticule, both in good size and quality, which one do you prefer and why?


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## tsuriru (Aug 9, 2017)

loong said:


> So a Nakayama and a coticule, both in good size and quality, which one do you prefer and why?



I would have to say both, but I would probably not use both of them for the same cutting instruments or even for the same cutting tasks. And again.... the question is hugely generalized. I have tried many MANY cotis and JNATS over the years. None of them where "the same" and none of them could (or should for that matter) be brought "up against each other" because its not all about the stone - its also about the steel, and the HT that a particular cutting instrument has undergone. And of course, there is the whole personal preference - completely subjective and varies widely from user to user. So there is no real comparison.


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## LifeByA1000Cuts (Aug 9, 2017)

Comparing oranges and tomatoes is an important consideration when choosing ingredients - and they can be used for the same tasks in some contexts, certainly not in others - why is it always discouraged?


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## tsuriru (Aug 9, 2017)

LifeByA1000Cuts said:


> Comparing oranges and tomatoes is an important consideration when choosing ingredients - and they can be used for the same tasks in some contexts, certainly not in others - why is it always discouraged?



Lets say I put a whole truck-load of cotis here and asked the avarage user to separate them into "sub-par" "good" and "super-fantastic". I suspect in this case there would be a completely different separation by each individual because this would probably be based on that individuals experience using cotis, the steel they use to test them, and their actual working experience with these stones. Same goes for JNATS. If I asked that the cotis be divided by vein type I seriously doubt most here would be able to comply - and the same goes for JNATS. This takes A LOT of experience and trying to teach this over the internet is like trying to give swimming lessons by correspondence. This is even before we ever get into comparing cotis with jnats or whatnots. but I think that most people are not ready to pay the price. they want quick fix answers of the absolute kind. so, here is a quick fix answer of the answer of thabsolute kind: Some things are not comparable to other things and trying to compare them is a waste of time, they are neither better nore worse than one another, they are just different. And BTW - I feel the same way about putting various steel types "up against each other" pretty much on the same grounds, although with some variation on the theme.


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## Razor (Aug 9, 2017)

loong said:


> So a Nakayama and a coticule, both in good size and quality, which one do you prefer and why?



I equate it to comparing Corvettes to Ferarris. A great Nakayama is faster and finer than any Coticule. That does not mean it is better for every purpose, but it is simply capable of more. That is why great Nakayama go for $3,000 and more. Although both mines are closed supply and demand is also a factor. Also, although a Corvette can go 0-60 and get around a track as fast as many Ferarris, the experience is completely different.


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## tsuriru (Aug 10, 2017)

Razor said:


> I equate it to comparing Corvettes to Ferarris. A great Nakayama is faster and finer than any Coticule. That does not mean it is better for every purpose, but it is simply capable of more. That is why great Nakayama go for $3,000 and more. Although both mines are closed supply and demand is also a factor. Also, although a Corvette can go 0-60 and get around a track as fast as many Ferarris, the experience is completely different.



So, if I sharpen a knife as sharp as it will ever be on a great belgian coticule and then put it to a Nakayama it can become sharper yet? Yeah.....thats the sort of marketing speak that sells Ferarris and Corvettes alright. Im not sure you are correct about speed either. There are faster and slower cotis as there are faster and slower Nakayamas, and certainly there are cotis that are faster than Nakayamas - So? is speed really a consideration? Are you telling me your sharpening skills are to a point where the only thing that surpasses your speed of motion and technique when you sharpen is the number of strokes the stone will require to get the job done? Do you despise sharpening so much that you are in such a hurry to get it over with that you would pay 10 times the price for a stone to insure this speed? Or are you just so busy it is worth the extra dime (even if they where quicker, which is unsubstantiated since everyone sharpens at a different rate anyhow)?


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## LifeByA1000Cuts (Aug 10, 2017)

Hey, I probably have the opposite take: The stone is splash and go, and can both polish/touchup - and with patience, sharpen - the knife very sharp without making a huge mess like a king or overpolishing like a superstone, so it is good


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## Blen (Aug 17, 2017)

Nice book about Belgian Coticule, in French


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## Noodle Soup (Aug 17, 2017)

Is the author the guy that mines them? I seem to remember his first name being Michel too. Talked to him several times at IWA in Germany. Any idea where I might find copy of that book?


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## Blen (Aug 17, 2017)

Noodle Soup said:


> Is the author the guy that mines them? I seem to remember his first name being Michel too. Talked to him several times at IWA in Germany. Any idea where I might find copy of that book?


Maurice Celis is the guy who restarted the mine in 1994. Probably they will sell it at their shop. If you can wait I am going to visit the shop end of October.


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## Noodle Soup (Aug 17, 2017)

Ok, thanks! I met a couple of guys at IWA with the company but it has been a few years (maybe around 2005) now and I can't remember their names for sure.


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