My new natural stone

Anybody seen one like this before? I cut this from a stone I found near a local glacial lake. Slurries up quite easily with an Atoma 400 and the slurry seems to "break down" like a JNat. I've used it on a test piece but not on a razor yet.

Cool rock. Dunno what it is, but I like how it looks.

Looks like a Amakusa.

Really cool looking stone

Petrified mammoth droppings.

Lol, I hope not! All kidding aside, it looks like some type of sedimentary stone. It's also quite fine. I'm thinking it will be at least a middling fine refining stone, possibly a finisher. Hopefully will try it out on a razor in the next few days.

Could this be a variety of sandstone maybe?

Here are some pics of the test piece I finished to give an idea of what it can do. I tried slurry on water and plain water and get a fairly quick cut for such a fine stone on slurry, but this seems to be more of an oil stone. Really cuts a lot better and finer on oil. Reminds me a lot of my black translucent Arkansas but honestly, better!

Here are shots of the natural side and bottom that I didn't cut off that might help with ID.

eKretz said:

Anybody seen one like this before? I cut this from a stone I found near a local glacial lake. Slurries up quite easily with an Atoma 400 and the slurry seems to "break down" like a JNat. I've used it on a test piece but not on a razor yet.

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Why should anybody have seen this anywhere if you picked it somewhere in the wild
I read the Found it over there Thread, so however great found, congrats !!

I really like that stone! Does the slurry darken easily while sharpening?

I haven't done a whole lot of cutting with the slurry yet but I will be trying some more soon - I have used the stone for a grand total of the one test piece and one razor now. The razor was finished to 8k on a Shapton Pro then I went to the new stone with a slurry and diluted as I went, but I wasn't happy with the finish on water, just like the test piece, so I switched to oil and that seems to wake the stone up. I started seeing black swarf with the oil where I didn't see much with the water, but I don't know if that's just because it takes so little steel off that it was just very dilute. With the oil I use the same procedure as I found that works best on my Ark - a drop or two then smear it across the entire stone face. The stone will absorb water very slowly, is almost like a Shapton 2k in that respect - very nearly splash 'n go. The oil just mostly sits on the surface, doesn't absorb hardly at all.

You may want to add your stone here;

http://badgerandblade.com/vb/showthread.php/254715-Making-a-hone

Here's a quick test I did on a knife - the sides of the knife started out with a pretty dull finish from a DMT 320 plate, so I didn't expect to see much of a difference in finish since this is a pretty fine stone. I slurried up the stone with an Atoma 400 for about 10 - 15 seconds then started honing on the side of the knife - I only honed on one side so I could compare. The slurry started to darken after about 20 - 25 strokes and I only honed on the side of the knife for a couple minutes. The pics show an original DMT 320 finish, the side I ground with the new stone (you can start to see the mirror reflection showing up, but the original's a really coarse finish so it's only showing in a few spots) and the stone after the couple minutes of honing - the darker slurry is from after honing, the lighter is fresh slurry I raised after honing for a visual comparison.

Very interesting!

With your original test on the round stock, is it possible for you to focus on the scratches that were left instead of the reflection?

OK here are the best shots I could get focused on the finished surface itself showing the scratch pattern with the lighting and angle tweaked to make it as visible as possible. I can do the same with a SG20k finish, so this doesn't really give a whole lot of info, but you can at least see the uniformity and fineness of the scratches. The few anomalous cross scratches are from another stone, just didn't get them all the way out.

Looks very nice. I wonder if harder examples from that area will prove to be even finer!

Quite possible, but I don't know, this stone is pretty hard. The scratches in the last pic aren't really representative of the finish, just like this pic is from a SG20k but it sure looks like it isn't very shiny at this angle and with this lighting:

I'm impressed. Looks like you've made a great find.
Id love to shave off that and see what its like!

Me too! I will be trying it out tonight.