Thread: Natural stone I.D. help please!!

Seems to be lots of Thuris saved these days, I'm happy to see them in good use again!
I bought one that the lady selling it declared "not a very good sharpening stone", she had tried it on her kitchen knives.

Sorry to go against the trend but looking at the pictures it doesn't really look like a thuringian to me. You say lapping needs many sheets of dry and wet sandpaper, means it is a quite hard stone and stone smells oily. That all isn't typical for thuri. Lapping a thuri normally could be done with one piece of corse sandpaper (60-100) to get it flat and maybe one or two finer ones (200-600) for polishing - no matter how deep the scratches are or how much the stone is worn out. Thuris are very soft stones.
Also the chips, corners and pattern seem unusual.

The light blue / green color reminds me on some special LI (or CF) stones. I got two examples of them where I also thought this could be thuris as I bought them. Here is a picture of one of them.





But anyway - it is really hard to say from the pictures. I wish you the best, good honing performance and fun with the stones whatever they might be!

I'm not saying that it's a Black Arkansas, but I do want to point out that Black Arkansas stone can vary from a Blue/Black/Grayish color to a dark opaque Black, to a Translucent Black. The slurry in the picture tells me that it's likely a waterstone of some type. It would take a LOT of sanding on Black Arkansas stone to get something like that.

From the pictures I can't tell whether it's a thuringian or another slate.

Here is one I got that looks similar to yours that I thought was a thuri, but still have no clue. Mine was a dark blue, almost black before I lapped it. Looked like it was heavily glazed. Has the same look to it when wet. I have gotten varying results with mine so still not sure where to place it, but I have never even held a thuri before so I have no clue what to look for. Mine was fairly soft though. The pictures are pretty bad cause it is actually a bluish grey color.

My biggest problem is, I have no experience with any sort of a natural hone. All I know is the edge I get off of my 12k nani which glides through the tops of my arm hair effortlessly.

I had some time to play around with this stone for an hour or so last night. I used a razor that needed some touch up, previously honed on a 12k nani. Also a razor I know that hones very easily. I raised a slurry and slowly diluted it with a spray bottle after about 20 strokes. I did this 4 times until I was left with just water.
I then did my regular stropping and did my usual arm hair check. It shaves arm hair just fine, but does not grab the arm hair tops like my Nani does.

The more I look at the stone, and the last few post pics, they look very similar to my stone. So Im guessing it may not be a Thuri. I know its not a black ark because the Ark I have made me take a bank loan out for a sand paper fund. This stone I did use 3 sheets of 150 grit, but I also removed a 1/4 inch of the stone to remove deep pits. I then used 1- 220 grit, 1 - 400 grit and 1- 600 grit. In comparing this stone to my other stones ( Norton 4/8, Nani 12k ) Lapping seems slightly harder to do.

I also took another long look at the stone indoors and also outside in the direct sunlight. It is a very dark stone, with a slight dark gray/blue to it. In direct sunlight, twisting and turning it to catch the light, it sparkles very, very small flecks.

No matter what this hone turns out to be, I did prove that it delivers a shaving edge. More time to play may result in better edges. I am still fairly new to all this so all I have is time. The next thing I will try with it is comparing the edge, to an 8k edge and go from there.

Thanks for all the help guys. I appreciate it!

Originally Posted by roughkype

I vote Thuri, too. An Arkansas wouldn't have shed all that slurry before denuding the sandpaper.

Did you get the oil out? That stone should probably not have been used with oil.

The visible strata are very interesting.

Let us know if it improves an 8k edge...

Yes it looks like one of the hard slate hones.....
They range from leaverite to pure gold thus the question does it improve an 8K edge.

If you cannot get the oil out use a little bit of liquid dish soap (Dawn is one)
and the water should wet the hone and help keep the swarf from clogging
the hone.

One picture showed a bit of purple in the slurry. It is possible this is
a garnet rich Belgian blue water stone most of which are a lot coarser
than a coticle. Again does it improve an 8K edge?....

Looking at the images I am optimistic that you have a nice rock.

I think you all may have overlooked one important indication of what the stone is. If you look closely on the backside of the stone at the tiny indentations you will notice that they are actually extraterrestrial footprints. Yes, the stone you bought at the Antique Shop is actually proof that the Earth was visited by extraterrestrials in the past. Wow! the oil smell may have actually been from their space craft!
Think it's time for a phone call to Coast to Coast and have this really looked at!

Slurry looks Thuringian to me, but when dry it looks more like slate. The truth may be in the honing since pictures arent the same as having it in hand.