What is it? What should I do with it?

I picked this up today at an antique store. Its very hard and very smooth. It has a large crack in the middle but I think I could still use it if I stayed to one end. Just wanted to have you guys try and identify what kind you think it is. After lapping for 10 min. on 400 w/d, its barely touching it. The minimal amount of slurry coming off of it appears to be a white/gray color. Ill probably have to go to a coarser grit to start. Any info would really help.

Attachment 114274Attachment 114275Attachment 114276Attachment 114277Attachment 114278

After some coarser lapping.
Attachment 114279

Black surgical Ark?

I have to agree I am thinking surgical black.

Which means its going to be a pain in ... to lap. Personally I used a palm sander with a 80 grit wet dry and worked up to 800 grit. I then took an old busted razor I got in a lot deal and rub that all over to stone with oil on the stone. Till it was completely covered in slag. Then clean off. Repeat. After that the stone should have a smooth surface that should have a bit of a shine.

Ya I can't believe how hard it is. Thanks for the info guys. Now I'll read up on surgical black Arkansas.

So I should just take it to work and use it for my chisels and block planes, is what I'm reading. I don't think it will take the place of another stone in my honing line up. Oh well.

i disagree completely!

Black Surgical Ark is a fine and dandy finishing stone (provided its properly broken in) I get crisp smooth shaves off my favorite Reynolds done on an Arky.

Quote:

---

Originally Posted by Magpie

i disagree completely!

Black Surgical Ark is a fine and dandy finishing stone (provided its properly broken in) I get crisp smooth shaves off my favorite Reynolds done on an Arky.

---

Ok cool. this is what I wanted to hear. Just stirring the pot. Any one else wanna add?

Yeah I mean if you read up on them they're good finishing stones just extremely slow cutters requiring in the neighbourhood of 100 laps to achieve what it's capable of.

It may take a long time. but on the other hand, they are very kind to the steel

I use mine as a finisher also and get great edges when I do.