Natural Finishing Whetstone for Japanese Straight Razor

Product: Natural Finishing Whetstone for Japanese Straight Razor, Quality: Average
Size: 10 x 9 x 3 cm (maximum values, measurement errors may occur)
Weight: 451g

Hardness: Rated 5 out of 9 for Japanese knives, and 7 for straight razors.

Regarding Hardness:
When a Japanese knife is applied, black mud is produced, indicating the stone is medium-hard.
When gently honing a straight razor without a nagura stone, it slips and does not produce shavings.
The honing feel is similar to a suita stone with many fine air bubbles.

Color/Appearance:
A mixture of green, light blue-green gray, and some yellow.
Contains black spots (sesame seeds), some of which are shiny.
Streaks also reflect light.
It is indistinguishable whether it is coal, quartz, or another mineral, but there is no harsh feeling when touched.

Usability:
Suitable for sharpening Japanese straight razors. Draw is slightly weaker than usual.
For Western straight razors, it is necessary to add parallel movements like playing a violin. The size is insufficient for textbook honing methods.

Abrasiveness:
It produces black mud, so it has some abrasiveness, but it does not seem to remove the scratches from medium grit stones, so it falls within the finishing category. For razor use, it is good as it does not shave off the steel.

Finish:
It leaves small scratches, so it does not achieve a mirror finish. It's a semi-mirror finish.
Honing with mud makes it slightly cloudy, but it still has a subtle shine.

Drawbacks:
The mud after use turns yellow. It is neutral or slightly acidic. When used for polishing, stone powder can get into scratches on the gold surface, causing slight discoloration. While there is room for improvement with methods like using baking soda, it is not suitable for polishing Japanese knives.
For practical blades, this is not a significant issue.

Comments:
A finishing whetstone that is neither particularly bad nor good. When purchased, it was said to be from Nakayama (Kato Mine), but this is questionable. The origin is unknown.
For sharpening razors, maintaining pressure and angle, and processing the burr are important, and as you become more experienced, it becomes difficult to feel the difference between stones in the finish.
Therefore, when evaluating the stone itself, there is little to report other than the condition of the gold surface, slippage, beauty, and the type of scratches it leaves. However, for a honing stone for razors, stones that leave more scratches can be faster and more practical for work.

The last photo is a magnified view of a Japanese straight razor that had a collapsed edge, after being honed.

Honest Opinion:
Since I am selling razors, I am also listing this whetstone, but I have priced it quite high.
Unlike razors that require maintenance, natural finishing whetstones only undergo quality checks. In my experience, I have purchased over a dozen natural finishing whetstones, and I have yet to find one with quality issues that prevents it from honing a razor.
If you use a leather strop for finishing, the results will be the same regardless of the stone used.
When strong light is shone on the stone, it appears beautiful. In reality, they are often quite plain.