I couldn't agree more with Bill. Mislabeling stones for the non-japanese speaking trade is a big business in the big city areas now. Even if your stone really was from that mine and that strata, you could not be sure of the actual layer, hardness, effective fineness, scratchiness, etc. You might even get a stone that is actually very good.. for tools.. but near worthless for razors. Better to buy from a known dealer such as Alex, Maksim, or others recommended here so you'll know it's been properly graded and you'll have a guarantee so you can return or exchange it if needed. You have very little chance of getting a bargain anyway, the shopkeepers can spot a ツーリスト from 1600 meters.

rs,
Tack