Recently I bought this "black Arkansas stone" from best sharpening stones. As i perhaps falsely assumed based on the description on the website that this was at least novaculite and not dunston like I have had in the past and was deeply annoyed over the purchase of.
When I was looking to buy this stone the description described it as an extra fine stone traditionally used to sharpen surgical and dental tools but the price being lower because it's only finished on one side and glued to the wood block.
When the stone finally showed up and I opened the package I at first got the sinking feeling that I had bought another dunston this time without it being pointed out. I looked the stone over and noticed darker patches that did not look like that cursed stone so I had hope.
Since the stone was lapped fairly flat if a bit course I decided to grab a wide chisel and "break it in" having done this I proceeded to take a sharpened but used razor and use this stone to touch it up. Seemed to bring the edge up ok tree topping arm hair and only lightly tugging on the beard.
Because I had already chamfered the edges and broke it in and didn't think I'd be able to return it I decided to use the band saw and cut it free from the wood. Having done this I lapped it to 600 grit, lapped as much of the glue residue off the back as I could.
The last pic is the close up of the stone post lapping. I then proceeded to do a quick and dirty specific gravity test which came out to an S.G. of about 2.76 I'm sure it wasn't super accurate since their is a tiny bit of glue left. Caveat emptor!