Search:

I wouldn't put a razor on it.
That flat area is for your hand to hold the stone with, not to hone. The flat area is also usually coarse compared to the fine bottom of the "V".

@ suile
Yours would be a gesswein stone. If it is really soft then it is probably a jewelry polisher.

That's a Norton crystolone slip stone for sharpening the inside of V shaped wood chisels.
It's "fine" grit - maybe 6k.

Not meant for razors. If you know a wood carver, they would probably take...