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It looks alot like the stone I just found in the Mystery hone thread.

Lap it down, immediately!

It's not an Escher - Eschers are too soft IMO to be used with oil as it would penetrate too far. And it is not the dimensions of an Escher, even the untypical ones, neither does it look particularly...

I hate to state the obvious, but what you have is a Douglas Oilstone!

Seriously, that does look like an interesting hone. Perhaps it is a 'brand' of Charnley, although I never knew they were...