Thread: Deeper Petrographic / Geological Researches of razor hones and sharpening stones

I wanted to report another Update for my researches. As many of you might now iam still in the search of the fine french razor hones beeing sold under the "La Lune" and "Special Stone only for Good Razors" Trademark. The comapany behind it was F.G.B.C....

I did contact a geologist from an University to further more research some samples of razor hones / sharpening stones under a deeper petrographic / geological point of view. This means thin cuts (cuts of the stone 30microns thin) plus a analysis with the petrographic microscope. Eventually SEM shots could be done...thats open till now...

My counterpart till now was really open minded and seems to be in generally interested into this topic. So till now this is only a short report but i hope this will get a deeper cooperation !

You all know that iam doing this stuff in the main focus as "community" projects so i also would like to ask as many people as possible to further more define Questions which might be relevant for this topics....i will try to further more explain later what the different researches are in detail good for.

Stones under focus:
Those are the stone samples which are actually in focus or in which iam intersted in to get some thin cuts done and get more details of the composition of abrasives. I also would like a professional analysis of which type of material we talk under a geological point of view. Often we have terms like slate, mud slate, quartzites, etc. which could be just a better "guess" then a professional interpretation.

#1 Special Stone for good Razors
Estimated type: slate/glimmer slate
Color: metallic gray/blue

#2 Pierre La Lune Violet
Estimated type: slate/mica slate
Color: red-violet with green inclusions

#3a SchwedensteinEstimated type: Slate/Mud Slate
Color: brown-red-green

#3b SchwedensteinEstimated type: Slate/Mud Slate
Color: gray-black

#4 Vermio Slate
Estimated Type: Slate/Shale
Color: dark black

#5 Thuringian Water HoneEstimated Type: Slate/Mud Slate
Color: grey-green

#6 Orange Shale
Estimated type: Quartzite?
Color: Orange

#7 Khao MenEstimated Type: Slate / Mud Slate
Color: dark black

#8 unknown Estimated Type: Quartzite ?
Color: beige/orange

#9 unknown StoneEstimated Type: Slate
Color: brown-bronze with green and red inclusions

#10 Bavarian FrankonianEstimated Type: Quarzite
Color: beige-yellow-grey

#11 & #12: Japanese Whetstones

Questions:

1. What do you think are the main factors to get a connection between honing properties of a stone and the geological interpretation in terms of thin cuts ?

2. How important is the analysis of "abrasive particle" content and "form of the particles" ? How important are other materials without any abrasive content ?

3. Youre Questions ? Anything you wanne add i should ask a geologist for in connection to natural sharpening stones ?

This is way above my pay grade. So whats your question? Tape or no tape? Lol. Keep up the good work Doorsh you are the true stone man.

Originally Posted by Hacker7

This is way above my pay grade. So whats your question? Tape or no tape? Lol. Keep up the good work Doorsh you are the true stone man.

haha :-) Ok thanks for your Input

I have a lot of questions bud, i'll probably email you. Id let you slice some of mine up but im not crazy like you.


So I get to buy all the sliced leftover hones for 65% off right?

Doorch,
Thanks for your work; I'll try to help with your three questions to the best of my knowledge;
1) A hone needs cutting particles, SiO2 along with its minerals is the most abundant natural stone cutting agent. I don't think geologic history of a rock is overly significant mainly because it's so extremely diverse.
Every single stone of the "same" type of an area, hone or not, had a unique history about its formation, and what happened to it these millions of years since it was formed... And it's a huge deal!
Differences in temperature even by a single degree and for a moment could be able to change its composition, floods that could penetrate the invisible, in the microscopic level layers of stone filling them with inclusions, movement of tectonic plates, or even heavy rain that could remove the soil or in some way bring them to the surface, and subjecting on the wear from direct contact to air, water or sun which is pretty much the death of a hone (aside from a few exceptions like the Arkansas stones but it would be rough for them too)...
Every single hone, rather, every single stone that exists today, and the fact that earth's surface is not completely composed of powdered SiO2 and Aluminum/Calcium salts, it's kind of a miracle, but the other way around exists as well; excellent stones that could exist today were "unlucky" enough to face the above conditions and not survive; in fact I would bet that we have lost countless hones because of the above reasons, whether we were too late, or our civilization was not old enough to have the chance to use them, let alone if we existed or not on that (imaginary) time. And it doesn't need too much time for a lot of hones to become useless; check out coticules and Jnats for example. Leave a piece outside for a couple of years, and that stone, no matter how hard it is will end up a useless bunch of flakes and useless even as a paperweight.

And not only that; the story continues! A famous hone, say a Jnat-nakayama for example, or Thuringian or WOA.... If they were found 10000 years ago, or 10000 years later, their performance would be unbelievably different, in either in a good way making it "softer/harder of faster/finer" or the opposite; completely useless material with its only use being utilized on road gravel, or cement industry. Stones evolve, like us, they are almost alive, follow the flow of time and change along with everything else on earth.

2) The content of abrasive particles is what makes a hone or a decorative piece of stone; if the percentage is low, the stone is bad. If high, it's good.
As for the shape, it's important too; round particles leave a smoother, mellower edge but are slower since they leave shallower scratches, and sharp particles with spiky corners on them, the ones that don't lose their corners really fast anyway, are very fast and perfect for fast honing. So, it is too absolutely important.
As for the rest of the materials a stone contains and work like binders, they are too far more underappreciated than they should. They are the reason the cutting particles stay in place, and determine the hardness of the stone as well as the rate these abrasive particles are released. Useless at first glance, but without them, a stone is not stone.
The optimal scenario would be for these particles to have the same composition as the cutting particles along with less than overly hard bonds between them; this way they too cut.

As for the third question, I have nothing in particular in mind right now but thank you.
Keep up the good work Sebastian, and, thank you!

You have a couple stones I really want to try, hope you didn't slice all your turkeys.



They are up there near #1 right now for stones to try/acquire. I'm going back to novaculite lately, fun stuff.

Thanks for doing this, it should really be interesting going forward with the tests

Thin sections, as we call them here are the classic way to identify the components of a rock. To those not familiar the rock is ground down and then put under a polarizing microscope which is a basic optical scope with some modifications.

The way I would go about this is get hones of known quality and analyze them to see what minerals they have. The only problem is there is way more to this question of what makes up a good hone and thin section studies will only give you very gross composition. It's the details that will tell you more and X-Ray Defractor studies will give you the exact composition with percentages of the minerals and the anion and cation percentages as well as way more to the molecular and atomic structure.

Why is there no estimated type for the Japanese whetstones?

Originally Posted by bluesman7

Why is there no estimated type for the Japanese whetstones?

Actually the samples i sent were only Naguras i do not known the origin of,
on the other hand i think we mostly talk about sedimentry stones when it comes to Jnats.