Thread: Reasons I feel hones have to be sedimentary

As far as the different colors/grades of AK stones, I suspect that the differences in color are directly related to the 'other' minerals in the stones acting as binder.

As far as the substrate being 'more' important, I suspect that it's more a matter of being 'just as' important.

Novaculite probably has a very different crystaline shape than the crystals in a coticule. (amathyst isn't it?)

Diamond, again, a completely different shape and structure.

I'm pretty sure that all of those 3 are harder then steel, but I STRONGLY suspect that if you were to make 3 synthetic hones using the exact same binder and crystals of the same size, the 3 would perform very differently.

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

You're on the right track I think, but you're confusing some things-

Originally Posted by McWolf1969

Hmm, good points Khaos!

The arkansas honning stone is one of the few natural stones out there that claim to have a progression of stones...ie., wa****a, soft, hard, true hard, black hard and translucent...they are currently graded by color and density.
They are primarily made of novaculite, whose crystaline structure is claimed, to range from 2-5 microns in size.

Novaculite is any siltstone (recall that siltstone varies from about 2 to about 6 micron) with that composition. Anythign smaller than 2 micron is not siltstone and therefore cannot be novaculite.

From wikipedia:
"Novaculite is a form of chert or flint found in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift of Texas. Novaculite is considered to be geosynclinal [this means that a build up of sandstone cause a sink basin resulting in the high pressure needed for partial metamorphism] highly siliceous sediments [quartz is a silicate] and may be a product of the low-grade metamorphism of chert beds. The strata were deposited in the Devonian Period and subjected to uplift and folding during the Ouachita orogeny of the Pennsylvanian/Permian Periods. Novaculite is very resistant to erosion and the layers of novaculite stand out as ridges in the Ouachita Mountains.
Novaculite is a form of microcrystalline or cryptocrystalline quartz. The color varies from white to grey-black and the specific gravity shows an increase from 2.2 to 2.5. The very hard dense rock is used as a whetstone. It has been mined since prehistoric times both as material for use as arrow and spear points and as sharpening stones.
The word novaculite is derived from the Latin word novacula, for razor stone."

My best guess is that quartz is the cutter and the chert is the cement of the stone. J-nats are also formed with chert as a cement IIRC, though I don't know what the clasts (cutting particles) are.

Originally Posted by McWolf1969

Based on my interpretation, of what your saying, truely the 'performance' grading should be done not only by density and color, but by the substrate(sediment) bonding material that holds the novaculite(crystaline structure) together? Since this substance is what determines how easily the novaculite crystals are released, while honing.

Performance is a massive coming together of cuttign particles- their agressiveness and size, and the cement- its tenacity, rate of wear, solubility etc. I feel the reason Novaculite is broken down into this or that grit by density is that all minerals have a specific density, ie, quartz will always be x g/cm^3, mica will always be y g/cm^3, and thus any variation in density is a variation of mineral content. If you really cared you could solve this using matrices but I don't really want to. For sake of argument here is an example using arbitrary numbers. Element x is a cutting particle, density 5g/cm^3. Mineral y is a cement, density 2g/cm^3. If a 10cm^3 sample is 10% cutting particle by volume, it's overall mass will be 23g (1cm^3*5g/cm^3+9cm^3*2g/cm^3), and its density therefore 2.3g/cm^3. If a sample is 20% cutting particle by volume its mass will be 26g (similar equation, substitute numbers) and therefore have a density of 2.6g/cm^3. Therefore, two samples of a rock both containing Y as a cement and X as a clast, and therefore the same type of rock, will vary in density due to the actual percent composition.
I just realised that since we dove of the cliff and are now into the nitty gritty of geology, we should differentiate rocks and minerals. Minerals are a PURE, HOMOGENEOUS substance, with a given DENSITY and set CHEMICAL PROPERTIES. Rocks CAN be pure mineral, but are typically mixes of minerals, and therefore vary based on percentage content. Granite for example, is an igneous rock containing mica, feldspar and quartz. The amounts can vary- black granite is high in mica, pink granite is high in feldspar, but they are both still granite.
Similarly, sedimentary rocks are defined by the minerals contained, but then also by the size of the particles of the minerals contained. You can have a sandstone and a conglomerate that are identical in percent composition, but are different rocks because sandstone is much much finer than conglomerate.
This is why novaculite is still all novaculite, even though the colour varies. It is a certain grit range, and specific minerals. The mineral percentage content varies, and as that varies, the properties of the rock vary, colour being the most obvious, but hardness (cutting power) and particle size (grit) vary too.

Originally Posted by McWolf1969

Most likely the density/honing capabilities, of the various stones is determined by this substrate (sediment,) rather than the novaculite itself?

Great thread, btw.

Thanks,

Mac

As I just tried to explain, it depends on both, not the novaculite. Novaculite is the name of a type of siltstone. The subrate determines how fast the stone wears (in J-nats it is hard, so they don't wear out, so the cutting particles smooth out and actually get a little finer, in coticules it is soft so slurry is easily formed and the cutting particles are released so they cut faster). The particles contained with in the substrate control the grit and speed of cutting. Diamond particles (DMT) obviously are much faster than garnet (coticule). Just as DMT C ("big" diamonds) is coarser than DMT F ("small" diamonds)

I didn't see howards input. Thanks howard. So rather than being simply sedimentary, they typically are metamorphic. But still, shouldn't they be metamorphosed from sedimentary rocks?

Just about any rock can be metamorphosed like say sandstone which then becomes quartzite. Its more noticeable in effect in sedimentary rocks only because those are less dense to begin with. With igneous rocks it gets more interesting.

Shale is shale because it is sedimentary and has a certain partical size. You can go through a whole range of siltstone and mudstone, etc depending on the size of the particles comprising it. Those of you who live in N.Y State go up to Wurtzboro and you will find an old abandoned railroad Tunnel. Its about 1 mile long and the mountain is solid slate there for the taking. (just be careful a chunk doesn't fall from the roof on you) Slate has perfect cleavage so that's why its been used as a roofing tile for a long long time. A few strikes and you can get great flat pieces.

In general rocks and minerals are usually found in certain associations. Most minerals that form as xtls are from the igneous state where as the rocks cool from the liquid state and if they cool slowly enough and have room xtls will form. The forces governing the formation of the mineral will determine the type of xtl you get consistant with the xtl system that mineral falls in. Though its not a common association you can have garnets in a sedimentary rock but it would have to be a very special circumstance. For instance the garnet I had previously presented here is formed in a schist which is basically rock with alot of mica in it and the garnets over time will weather out of the schist and just be loose. Most times they will just either lie where they are and weather away of be carried else where and do the same but they can also be washed somewhere so they can find themselves in newly formed sedimentary rock over time of course. Of course this is theoretical and I don't know if such deposits do exists but I would imagine they do.

Like what Howard said that's why I'm going to experiment with that chunk of beryl I have.

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.

I respectfully disagree. Pheasant lane down the road from me is one block long and has two deads ends.

Originally Posted by khaos

I respectfully disagree. Pheasant lane down the road from me is one block long and has two deads ends.

yes but it doesn't lead to Rome.