Please help identify stones

Got this 2 from ebay. And dont know what they are.
I hope that you guys can help.
They was used with oil very dark color black-gray
Stones are in the harder side, not soft ! Slurry is white.
size: 205mm 50mm 25mm
small one is 115 mm 35mm 15mm

here is pics:
https://lh6.googleusercontent.com/-2...0/IMGP4770.JPG
https://lh4.googleusercontent.com/-3...0/IMGP4771.JPG
https://lh4.googleusercontent.com/-s...0/IMGP4773.JPG
https://lh4.googleusercontent.com/-5...0/IMGP4775.JPG
https://lh5.googleusercontent.com/-H...0/IMGP4776.JPG
https://lh5.googleusercontent.com/-q...0/IMGP4777.JPG
https://lh6.googleusercontent.com/-M...0/IMGP4779.JPG

Thanks

If that genuine blue was made in the UK as it states, then it is likely to be a type of slate, possibly Yellow Lake sharpening stone or Dragon's tongue, there being several variations within both types, but I am taking a guess. Others will follow suit to advise as to their distinction. If they are the latter varieties then they were not, although can be, intended for honing razors, and you will likely find that something finer is preferable though not essential, for finishing a razor's edge.

Have you attempted to hone anything with either of them?

Yes i did try it out today, and shave bit finer then coticule, but yes it can be Yellow Lake
More suggestions is welcome :)