Same here, Alan. Stone in hand and fingers straight out and you’re safe.And there I was thinking it was a stone with some beautiful black and red marking...
I almost lost a fingertip one time in gripping the broad sides of a coarse DMT whetstone while honing. Never did that again. From then on, the hone has always rested on the palm with the fingers completely outstretched. I do get cuts like yours sometimes during an extended lapping session or when flattening a stone found in the wild on a belt sander.