Might be better placed in the Hones forum but i was linking an auction i just seen, so i thought best to put it here.

Just browsing at the bay and i saw this,
NATURAL GREY/GREEN V.FINE SHARPENING STONE RAZOR HONE WHETSTONE CHARNLEY FOREST? | eBay
It looks very perdy and i dont know what it is, looks to be slate of some kind.
Just thought i would drop it in here incase its something someone had been looking for, love the "charnley forest? listing hehehehe