Case solved. I have been research a stone I just got one in a barbers case that I just purchased. I'll have to post a pic. Definitely the same as yours, Mine is 5 x 2.5 and came with the slurry stone exactly the same as the main stone, which had me scratching my head for days. Similar slurry to escher.

Thought it might have been a Black Arkansas, or even a French La Luna, but I had never seen either of these with a slurry stone. Once I honed a razor on it, I realized this is a pretty special stone, leaves a polish on the bevel similar to an Escher, but cuts much faster.

My new finishing stone!

Awesome, great post! thanks! Ill post mine tomorrow.