Thread: New Natural African whetstones - followup

Hi Salsa,
I'm keen of course for some guys to test out these stones if of interest to anyone, but at this stage I'd like to wait for some of the real stone pros to comment and offer their expertise first.
Thanks for your interest though.

Originally Posted by Jasper Kade

Thanks Jim, your interest is much appreciated indeed.
It would be great if you managed to share with me anything you learn regarding the geology of Japanese naturals..
This new info I've posted above regarding Hornfels seems very likely to be where my stones fit in the spectrum, but, I'm still questioning a few things: Firstly, if Scotch hones are indeed 'Hornfels' (indurated shale) then why have I never seen any images of Scotch hones with any orange-red parts, either in the matrix or on the sides etc of the hones? This leads me to believe, as the excerpt above explains, that the orange-red patina develops WITH AGE, so perhaps the scotch hones are younger than my African stones? Perhaps the article is specifically referring to Hornfels from Southern Africa, and this orange skin/patina is location specific?

But then again, there is no denying the visual link between my stones and Japanese naturals, so what is the connection between 'Hornfels' and the Jnats, are Jnats perhaps a form of Hornfels as well? I know some Japanese stones do have a similar speckled/dotted appearance like my stones and indeed the Scotch hones, so geologically there seems to be a link between all of them...

Jasper,

In "The Charm of Kyoto's Natural Hones" <<京都天然砥石の魅力>>, the only mention of Hornfels I've found is in reference to a thick layer of stone ABOVE the hone seams. A rough translation is "...on the upper side, the Toishi layers are pressed by a soft stone, which breaks into horn-shaped stone, which is called "Fang" (Hornfels)."

This is also called "Chert" in the book, which is confusing...

I'm afraid I lack the vocabulary to deeply discuss the issue as of yet, but I am working on it.

Thanks Jim.
Agreed. From more research it seems 'hornfels' is a very broad term to define indurated shale/mudstone etc. The resulting stone material can be any number of shapes/colours/make-up based on the orginal source shale etc. And there seems to be a fine line separating indurated shales and cherts, in that the two terms can be interchanged depending on the sample.

Still, there is a correlation between cherts, hornfels and such and their use as hone stones. So I reckon my stones are somewhere in this general area.. Specifically the white tam o'shanter hone. I've seen pics today of a close up of one of these and the fine black dotted appearance looks strikingly similar to one of my stones.

Also though, not all my stones have that dotted appearance, some are cleaner with green/beige swirls and almost 'camo' in appearance. So it's still sort of unknown EXACTLY what my stones are.

I need to get me a scotch hone and a Japanese natural, so I can compare and analyse more effectively


Regards,
- Mike

Since Africa has no long tradition in using steel, such as Europe and Asia, I am not surprised that someone finds usable hones there, that no one has found before. The invention of artificial hones made the search obsolete, too. I could think about something similar in Australia…

Have you shaved with razors honed on them? I wouldn´t bother too much about comparing them to other stoned, but how their actual performance and the shaves are.

Great find, by the way.

Regards,
tok

Thanks Tok,

Yeah I've tested some razors on them, but not as yet properly honed any to shave with.. at this stage I'm just speculating as to what they stone material could be..and hoping some of the guys have some input and knowledge to contribute to hone stones in general.

Your comment on synthetics making the hunt for naturals obsolete is quite valid, and is largely the way I'm thinking these days when I come across any deep contruction digging, or see an outcrop of stones in the field Nature is so infinately diverse - it's a part of this hobby that really interests me.

cheers,
- Mike

This is just a friendly reminder to keep all solicitations (asking to buy/ discussing selling etc) private via PM.

This discussion regarding the nature of different naturals and how they relate to the hones in the OP is fine so long as you all don't let your HAD go public here!

Thanks and enjoy.


-Rob

Pic # 13 & 15 resemble the 3 TOS that I have but the speckles in your hones are much finer and have a greater color variation in the stone than the TOS has.

What you have will most likely be suitable for razors at some stage of the honing process or at least some of them will. You will just have to try them to see where they fit.

How your hones compare to others, Jnat, TOS, Coticules,German waterstones , slates,sedimentary rocks, would need to be compared by a geologist/chemist. If they were created by the same process or during the same geological time frame would take a whole bunch of work by specialists.

I envy you having this wonderful time of discovery. I do hope it works out for you.

Thanks Randy, and thanks to all who have shown interest in my rock specimens

I really just wanted to show my process of discovery here, and strike up some discussion on the subject of natural honing stones, as it really fascinates me, especially since I'm from such a far-flung corner of the globe.

Thanks Randy for your comments on the Scotch hones, I see a clear correlation to those stones from Scotland, and so I imagine the stones I've collected are at least in that family of stones, geologically - and I think that's pretty cool.

Of course, as I get more time I'm going to cut the stone into standard hone shapes and properly test them myself, then perhaps report back here if anyone finds this type of thing interesting.

Kindest Regards
- Mike

I recall from highschool that millions of years ago Africa was attached to another land mass before earthquake and tectonic forces caused our continents to move. I think this was what they called Pangea?? Does anyone know what Africa was attached to back then? The answer might help you match up the rock samples.

Originally Posted by Salsa

I recall from highschool that millions of years ago Africa was attached to another land mass before earthquake and tectonic forces caused our continents to move. I think this was what they called Pangea?? Does anyone know what Africa was attached to back then? The answer might help you match up the rock samples.

The origin of the natural stones mined near Kyoto are in the sea near Hawaii. They went west to Japan.
So if there are sediments which has been build more east of Hawaii they could have traveled east to America and not to Africa.