Very Unique Looking JNat, an expert opinion is appreciated

[AljuwaiedAK]

This is very unique looking JNat, it is black with golden nashiji, I bought it directly from Japan, the seller claims that it is a vintage stone from Narutaki mine, however no one know for sure as there is no stamps.

The stone is very dense it weighs 720g !!! pretty heavy for it size (5x3x1), however it is not very hard it is 4.5 or so, fast cutter with hazy finish auto slurry if enough pressure is used, the shave is like a coticule yet sharper but not as sharp as an Escher stone. I have few Narutaki stones, one is stamped and it has the same aroma only this one is more potent.

I Hope this help in finding more information about the stone, maybe Stefan, Alex or some of our JNats experts can tell us more about such stones.

Regards,