Eric isn't lying that slate is AWESOME. So nice in fact I was willing to trade a piece of Asano Koma nagura for a slab.(Hope you are enjoying it).
possible thuri - Album on Imgur
I got a new 8x2 dark blue stone in which I thought was a silkstone at first but now I'm thinking possible thuri. It is too thin for a silkstone. It is soft(lapped super easy but no auto slurry so far) and fine with a velvety feel. The slurry dries white also. It produces a great edge so even if it's not a thuri it's still a keeper.