That's really unique, Simon. I have a lithide, but having the same hone design in the Tam snakestone would be ten times cooler, not to mention a natural stone vs. manufactured like the lithide.
These hones were probably used on un-coated carbon steel blades. Those are rare these days,
though one example is the Treet Blue Special. Anytime you used this on a new blade that is
coated with Platinum or PTFE, you're removing the coating and probably leaving a much duller
edge on the blade.