Thread: Is this a combo coticule?

Yes, there are glued combos.

This one looks a bit like slate, not Blue - but it may be just the photo or dirt. If it's purplish when you clean / lap it - then you are in luck

Not PITA to use at all (at least - not for me) - I'd cherish it! I'd also venture that the yellow may not be very hard, some vintage coticules are kind of soft

Cheers
Ivo

I have a glued combo and a natural combo. Looking very closely at the first picture I feel like I can see the garnet matrix in the side of the blue. However, the picture showing the break looks more like a cleave line for slate than my broken Belgian blue. Obviously this is not definitive in EITHER way, but I am leaning towards this being a combination stone. In order to tell, find an eye loupe or hand magnifier and have a look at it. If you see a matrix of inclusions in the stone, these are almost definitely going to be garnet, making it a Belgian stone. Of course the lapping test will work as well.

Once you lap it you'll know in about two seconds if it's a blue. Purple slurry = blue belgian, it's that simple. As for the color of the rock itself, that can vary – anything from blue to purple to just about black. I have a natural combo where the blue doesn't look blue at all, looks jet black. But somehow the slurry always looks the same, purple.

I agree with Ivo that vintage coticules are often softer. My finest coticule is actually very soft.

Thanks everyone for all replies. Dumb question but how do I lap the stone? Do I buy one of the little niigura(sp?) stones for the slurry or should I buy ne of the course DMT stones? Thanks again.

One clue might be the yellowish rock on the bottom. It looks like one of my naturals. It could be coticule vein on the other part of the blue.
To me the dark looks like slate though. It might be my monitor adjustment. Not sure due to the different factors. MikeB

it also looks more like slate than blue to me, but yes, lapping will tell you right away.

Originally Posted by proon73

Thanks everyone for all replies. Dumb question but how do I lap the stone? Do I buy one of the little niigura(sp?) stones for the slurry or should I buy ne of the course DMT stones? Thanks again.

If you're cheep you get a wet/dry sandpaper in the (300-500 grit range) and a flat surface - marble, glass, etc. Then under a running water you make figure 8 w/o much pressure. You can pencil a grid on the stone and when it disappears, the stone will be as flat as the sandpaper on the other flat surface. You can then run it quickly on finer grit sandpaper, to get it a bit smoother, but I don't think it's necessary at all.
Alterjatively you get DMT coarse (325 grit) and do the same. This hone is spec'd to be extremely flat and I find it works much much better than sandpaper. But it's more expensive.
As far as slurry stone, as you like. Depending how soft the stone it, the honing can prodice slurry on its own. Or you can use a junk razor to raise some. But that's the cheap-o version. Using a slurry stone is much nicer.

check out http://www.theperfectedge.com/belgian.shtml they sell these stones and have info on them

"These stones have a base of slate for added strength. They are not combination stones. The slate backing will not sharpen steel"

"Natural Combination Stones
We occasionally receive a natural combination stone from the quarry that is yellow coticule on one side and blue on the other. They are fairly rare and come from the spot where the yellow vein of coticule intrudes into the blue stone. To my knowledge, they are the only known naturally occurring combination whetstone. The 8"x3" size is $250 and the 6"x2" size is $130. We occasionally receive an 8"x2" and that is priced at $160. Call to check on available stock. "

Please note that in the above posts people already mentioned that combo stones DO exist.

Check the slurry on the darker side. If it's sortof Puple-ish then it's a belgian blue. And it'll be a combo then.

Personally I think it is...but then who am I to put myself forward

Originally Posted by LX_Emergency

I've got a blue....and I've got a yellow...and that looks like a blue/yellow combo to me.

+1.
Looks like it to me also.

John P.

it is definitely a blue. The slurry from the lapping was purplish. Everyone here said that would definitely decide it. Thanks everyone. I used the yellow side to hone my Henkel's. I then went to the chinese 12k afterward. For my first honing job, I don't think I did too bad. I am trying to set a bevel on another razor, can I do it on he norton 4k? Or should I buy a norton1K? Thanks again.