Thread: Hones and Geology

Hi Guys,

I've been thinking about natural hones lately and so I'd just like to put a few questions out there to anyone who may know..

I live in South Africa - a country rich in various minerals and natural resources ie. platinum, gold, diamonds, copper, coal etc etc.. So I've been wondering why not rock/stone appropriate for sharpening steel? Surely the 'known' spots on the planet for hauling out rock that's good for sharpening aren't the 'only' deposits..? I mean, hones aren't exactly big business like platinum and gold, so I doubt much energy has gone into exploring the earth for new hone-stone deposits... you know..?
I live in a region known for this band of very old sedimentary rock that makes up much of the landscape (shale/slate mostly) and this is what got me thinking about it all. I mean I've looked at images of Japanese natural hones, and seen the raw rock etc, and it just looks so familiar, like "I've seen rock like that a thousand times before.." I also dug up some small pieces of what looks like hard black shale or a type of slate I suppose - in either case, it's sedimentary rock that is fine-grained and made up of high quantities of quartz or mica.. So I lapped a small side of it, though it was pretty smooth from the ground (has the same shine/smooth feel as my BBW) and when you rub two pieces together it forms an earthy smelling, white slurry...
My final test was to rub the back of an old razor blade on it - just light back and forth strokes over the lapped spot with the slurry - and guess what? A bright, shiny spot on the dull steel - brighter than the spot my coticule created right next to it.. So this leaves me thinking if it's just CRAZY to think that if I got a larger piece of this sedimentary rock, cut it to the right size and then lapped it and used it, would I be able to call it a 'proper' hone? You know what I mean?
If it abrades metal, and looks and works like a hone, then surely it's a hone...perhaps even a 'notable' hone, who knows..

So I guess here are my questions:

1 - What exactly are coticules, covenant stones, thuringians, Japanese naturals, etc etc? (from what I can gather they are all 'sedimentary' rocks, altered to some extent through time/pressure/heat to have the right quantity of metal-cutting elements.. ) But what exactly are they classified as? When a geologist holds a thuringian/escher stone, what does he or she classify it as?

2 - Is it rational to assume that perhaps there are other deposits of 'hone worthy' stones in different regions of the planet, that we don't have the definitive list of good hone stones, and that due to the random nature of the planet and of one stone from another, that any suitable sedimentary rock with metal cutting ability could be deemed a Hone?

Guys this is a long ramble of a post, so sorry indeed for that - I'm hoping I'm not the only one to have thought about all this, and so it would be great to hear some of your thoughts..

Cheers,
- Mike