Thread: Reasons I feel hones have to be sedimentary

Please correct me if I'm wrong, argue with me, but as we all search for new stones, some people are considering things like Jasper... (?) and I think this is largely wrong/highly labour intensive. After seeign this in two or three threads, and posting in both I thought it might actually be better to post it in it's own thread for discussion, so that before we all go out and find some mineral with Mohs hardness 9.9999 and more common than air, we find out what is important to a hone. Please read:

I"m just tossing my two cents out there for the world. Thinking about the mineralogy and material properties, shouldn't all hones necessarily be sedimentary rock? My thinking is this:
Hard particles in a soft substrate is like sandpaper that refreshes itself. If you have one hard thing it is like a chisel or a knife or a grater. Think about this on an extreme level. If I have a stone with a profile like this /\/\/\/\/\/\/\/\/\ and it is a single hard stone that is harder than steel, it's gonna cut gouges in the steel equal to that, and never really smooth out. Think cheese grater. If those cutting peices are glued together with something softer, they will break off and smooth out. Where this "glue" is soft, like coticule, it will continuously refresh itself, and cut a lot faster with a slurry. When this "glue" is hard, the cutting particles will eventually smooth out a little, like a J-nat. When this glue is solid, or if the crystalline structure is solid, the grit has to be built in. All sandpaper is alumina or SiC or whatever, just different size pieces. Or DMT. The diamonds are the hardest thing known to man, and the way they get different grits is not by changing the hardness or mineral properties of the diamond, but the GRIT of the diamond they embed. So while Jasper (or quartz or tigers eye or cats eye or corundum or diamond or sapphire or ruby or hawks eye or feldspar or topaz or chrysoberyl or chromium or boron or beryl... you get the idea) is harder than steel, that is not important. Its the finish you put on it that will be important. Lapping with a DMT XX will give you a rough hone, lapping with a DMT C a smoother hone, DMT F a smoother hone yet, etc etc. And the grit will not correspond, ie, lapping with the DMT C (325 grit) doesn't mean your jasper hone will be a 325 grit hone, just rougher than if it were lapped with the DMT F (1200). My best guess for this success is if by trial and error through different lapping treatments you came up with a progression, or if you only made one rock, you made is smoother than glass (very literally) to be used as a very final polisher, probably around some astronomical grit, as it wouldn't do any honing, only polishing.

The evidence I'm guessing behind all this is:
-All man made rocks are sedimentary- SiC or alumina or something harder than steel, BOUND BY something softer than steel, polymer, clay, ceramic, etc.
-The exception to this is carbo stones, because carborundum is harder than steel, and we all know what a bitch it is to lap a swaty or a carbo. If you look closely at them though, they are not a single crystal, and I suspect they are sedimentary in nature, where the sediment is SiC powder (SiC is commonly known as carborundum)
-Grit and Hardness have no correlation- all DMTs are diamond, SiC sandpaper comes in all grits
-If something is harder than steel (roughly 7 or higher on the Mohs scale) steel will do little to wear it down, and it will EAT steel (try taking a coping saw to a DMT)
-If something is softer than steel (roughly 6 or lower on the Mohs) it will barely touch steel and steel will just wear it down. (try cutting steel wire with a knife shaped piece of shale)
-All confirmed location hones to date are sedimentary- Thuringens, Coticule, BBW, J-nat, the British Isle shales, Arkansas, Turkeys, etc.
-While Sham's hone MIGHT be jasper because it LOOKS like Jasper, until it is evaluated by a minerologist I'm skeptical. To me it looks like a sedimentary rock, just not with clear striations. If you want I can post pictures of limestone or a piece of shale I use as a paper weight, neither show striations, both are sedimentary. Olivia, please can you ask your brother about this?
-Diamond paste is all ground up diamond, just in different sizes, and the size determines grit
-IIRC Shapton Glass Stones are only mounted on glass, they are actually polymer bound (sedimentary again), why wouldn't they just make a hone out of Silica Glass (SiO2, same as quartz)?

So as a summary, we need a sedimentary rock, with a water soluble base softer than steel, and cutting particles harder than steel. While igneous/metamorphic/crystalline minerals and rocks can work... I don't see the practicality in having to have 10 slabs of them, all lapped differently (and probably inconsistantly I might add, given natural variance)

In theory any mineral harder than steel will wear steel and can be considered as a honing medium. However its way more complicated than that. Even softer stones can be used to hone. Remember the Grand canyon was formed from running water (in general) and granite will fall apart to mud and sand when exposed to weathering.

really its the type of particales, (minerals) the particale size and shape and the base rock that all plays a factor. I would think using a massive rock like say slate or a chunk of quartz as a hone might very well work to hone an axe or do preliminary honing but for finishing and for delicate work with our razors I'm not sure it would. Of course there are some non sedimentary rocks that are quite soft. I guess you can experiment with stuff like marble or fluorite or apatite or asbestos based rocks or talc and see what happens. If you use the stuff and its softer than steel it will work the way our usual hones work anyway by having the residue break off and becoming smaller and smaller like a slurry so...

Thats what I'm saying... You have to have hard particles to actually cut... The medium of the stone can be anything though. If its a solid, smooth crystal... how can it cut? Thats my main question.

I've alerted Howard Schechter to this thread. I'm interested in what he has to say on the subject and I'm interested in this subject in general.

Chris L

Well, if it's a really hard stone--much harder than steel--and pure, then won't the stone work like a diamond plate, basically? Rather than particles breaking up and doing honing, it will be a very hard surface that takes the finish that you give it and KEEPS it?

Isn't this, in fact, how the spyderco hones work?

The coticule site is metamorphic and not sedimentary. You wouldn't find garnets in a sedimentary rock. They form as a result of the heat and pressure applied to a sedimentary rock. Metamorphic rocks are therefor considered a separate class (Igneous is the third broad category). The escher stones were likewise metamorphically formed.

Jasper is just as likely as anything DEPENDING on what you're honing. Even leather has an effect on steel. Last year I photographed a Jade hone of Inuit origin at a museum in Sitka, Alaska. Jade is really soft but that's what they used.

The hardest steels are around 5.5 on the Mohs scale so anything above that such as garnet, quartz, corundum, carbide, diamonds, topaz, etc. will abrade steel. Hones don't necessarily have to be sedimentary. Even the slate hones of Wales are slate which is metamorphosed shale - much harder than shale.

My two cents!

Thanks for your input, Howard. But......now I want a hone made out of topaz!!

Chris L

Originally Posted by Howard

.....Even leather has an effect on steel. Last year I photographed a Jade hone of Inuit origin at a museum in Sitka, Alaska. Jade is really soft but that's what they used.....

I do not agree with the idea that the sharpening medium MUST be a sedimentary, metamorphic, or any other type of stone....it doesn't even have to be harder than the steel you are honing for that matter!

Like Howard said, the Inuit used Jade to sharpen even if it is relatively soft (softer than steel), in fact I have a friend that recently got a chunk of Jade and currently uses it for a final polish to his edges...although he says it requires the use of a chalk type nagura to help keep the blade from "sticking" to the hone, and he says it's a bit slow but leaves a pretty polished edge.

The same person using the Jade stone has also used Flint, Chert, and Obsidian to hone with. He said his stones compared something like this...Flint seemed to be a slow cutting 6K, Chert seemed to be a slow cutting 4K, and the Obsidian seemed to be a slow 6 to 8K. So lots of these rocks have actually been tried and found to be perfectly serviceable stones to sharpen on, even if they are a bit slow.

I have tried everything from plain copy paper and newspaper to wood and leather, and each with and without several types of polishing compounds trying to get some form of polishing done....ALL have been successful to some degree, and work better for some purposes than for others...not just razors or even just knives.

I guess my point is simply that there are MANY ways to skin a cat and they all have some merit.

Your exactly correct.

Like I always like to say the Grand Canyon was formed by running water with a little help from uplift.

The point is that over the years people have come to use (with razors) certain things they find work well, are reasonably fast and economical. But that doesn't mean you can't experiment and use unordinary means to hone your razor.

All roads lead to Rome.