Geology of Jnats

[Altadan]

So,

I just got my first every tiny-weeny-itssy-bitsy jnat (a takashima tomae), and I'm in seventh heaven.
Except,
that now I want more, and I can't afford the prohibitive costs of these pieces of rock,
which got me thinking about their geology.
Sure, the U.S offers Arkansas stone, and Europe has the Belgian blue, but come one now, can it really be all that there is? Surely not.

So I figured I'd start asking here - what are those Naturals made of? They strike me as sedimentary, so, some dense (hard?) strata of limestone? Various substrates accounting for the various "grits," with a melange of other basic elements adding color (such as the blue aono?)?
EDIT: I'll start with Wikipedia, and move on from there, but if any of you is a geologist - and happens to have some cheap carbon steel we can test on, I'm offering a partnership ^_^

What is it? Because I've been lying awake in bed thinking of the various places I've hiked in my life, where I should possibly pay a second visit with a hammer and chisel...

[gladius]

Sandstone, claystone, quartzs-trachyt, tuff, andesite, ganister, silica shale, etc... is abundant but specific qualities are not.

These are silica shale from Pakistan that work very well.

https://www.theperfectedge.com/product- ... terstones/

[Altadan]

Nice!

I'm currently searching the web for deposits near Dallas (well, Arkansas, obviously, and parts of TX and OK).

[nakneker]

Interesting thread. I hope you get lots of feedback Dan, I've wondered the same thing.

[Lepus]

Natural whetstones are present elsewhere, almost certainly with much more variety that than found in Japan. The question is whether anyone has mined them, graded them, and tested their suitability to aesthetically polish steels at various hardness in a variety of ways. No other culture I know of has had call to so finely distill their natural stone use and classifications. With Japanese stones you're looking at the cumulative knowledge gained by millions of hours of trial and error that is no longer being conducted and will never be conducted again. Synthetic abrasives cut faster and cleaner than natural abrasives, so for anything but the most esoteric purposes natural whetstones are outdated to the extreme. Even in Japan where this was taken to an extreme most of the mines are closed. I doubt even a geologist in a related field has such specific knowledge about the precise ratios of abrasive and concentrations in different stones that they could shed much light on this. You'd be looking exclusively at gathering information from natural stone aficionados and I guess some really devoted historians.

[J david]

Lepus,

Post of the year nomination.

Congrats.

[gladius]

...their suitability to aesthetically polish steels...

---
Only the ones that fulfill all of the below conditions are qualified as sharpening stones.

• Harder than steel.
• Fine enough to sharpen the blade to desired sharpness.
• Sharpening particles are dispersed evenly.
• New sharpening particles surface as you sharpen.
• The lubricant (water) can be absorbed to certain extent.

ref. http://japan-tool.com/tech_knlg/toishi/Awasedo.html

[Lepus]

That definition seems a little strict to me, though certainly nearly necessary for a stone to be used in the Japanese style of sharpening. At the very least they would be good criteria by which to gauge an unknown stone if someone wanted to try to pick up a random rock. Do awasedo that require the use of nagura to draw out abrasive meet the forth criteria? Are stones traditionally and effectively used with oil excluded?

I have entertained these same thoughts myself and I know Mark at one point considered asking geologists at the University of Wisconsin about natural whetstones. The upside is that, once you understand natural whetstones for what they are, rocks, you realize that potential natural stones really are all around us. You could just get lucky if you go looking with some basic information, the likes of which a geologist could in fact offer. I've sharpened knives on two pieces of sandstone rubbed together to create a flat surface just to see if I could, and indeed I can.

[gladius]

Do awasedo that require the use of nagura to draw out abrasive meet the forth criteria?

---
I'd say they do but at a much slower pace, hence the need for a nagura.

[nevrknow]

That definition seems a little strict to me, though certainly nearly necessary for a stone to be used in the Japanese style of sharpening. At the very least they would be good criteria by which to gauge an unknown stone if someone wanted to try to pick up a random rock. Do awasedo that require the use of nagura to draw out abrasive meet the forth criteria? Are stones traditionally and effectively used with oil excluded?

I have entertained these same thoughts myself and I know Mark at one point considered asking geologists at the University of Wisconsin about natural whetstones. The upside is that, once you understand natural whetstones for what they are, rocks, you realize that potential natural stones really are all around us. You could just get lucky if you go looking with some basic information, the likes of which a geologist could in fact offer. I've sharpened knives on two pieces of sandstone rubbed together to create a flat surface just to see if I could, and indeed I can.

Like the upside down ceramic mug trick?

[Jeff B]

I sharpened an old knife on a brick once, does that count as a natural stone?

[Altadan]

I sharpened an old knife on a brick once, does that count as a natural stone?

Brick is synthetic, no doubt.
I flattened my stone on the sidewalk, too. Cheap ain't always better though

[Altadan]

So, this is my next question;

If novaculite is one variety of naturally occurring stone, are there others?

[Jeff B]

I sharpened an old knife on a brick once, does that count as a natural stone?

Brick is synthetic, no doubt.
I flattened my stone on the sidewalk, too. Cheap ain't always better though

Damn, maybe someday....

[gladius]

So, this is my next question;

If novaculite is one variety of naturally occurring stone, are there others?

---
um...yes
Most every stone you find in nature is uh, naturally occurring. During a visit to DC I spent an entire day at the Smithsonian Museum of Natural History in their Gem & Mineral section. Wow it was so fascinating!

https://www.google.com/search?q=smithso ... 03&dpr=1.1

[Jason H]

You can melt your brain by looking over American stones:

http://www.tomonagura.com/Escher-Razor- ... -hone.html

[Kit Craft]

You can melt your brain in general over Keith's site. Add that to his posts on the razor forums and you have years worth of reading...lol. He has a youtube chan too.

[Altadan]

So, this is my next question;

If novaculite is one variety of naturally occurring stone, are there others?

---
um...yes
Most every stone you find in nature is uh, naturally occurring. During a visit to DC I spent an entire day at the Smithsonian Museum of Natural History in their Gem & Mineral section. Wow it was so fascinating!

https://www.google.com/search?q=smithso ... 03&dpr=1.1

Ok ok,
I meant "natural occurring sharpening-stone"
I understand that any stone will sharpen, but I'm talking strictly about those that would do it well.

[Altadan]

So,

I found out that in the Levant (namely Lebanon, Syria & Israel) there used to be found a stone known as Pierre du l'Est \ du Levant.
Not much info but the visual in these two:
https://www.youtube.com/watch?v=khMAwXe8N1A
https://www.youtube.com/watch?v=5EIe-e6yP64

An online store (The Perfect Edge) claims to bring in a stone from Pakistan...

and with regards to the U.S,
Tell me, most revered forumites - Ken & Kit, please chime in - why don't we hear more on this forum from Arkansas Stone users? What's up with those?

[gladius]

Arkansas Stones are slow though do polish well.

Let's not forget the Italians...



...and Russians...



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