Grit Table / naturals / Nakayama (awasedo)
Product, no maker data
Natural stone
This line has a measured particle size, rare for a natural stone. The microns come from published measurement rather than a grit-number estimate, so they are drawn at full strength, not faded.
Each grade below shows its size in microns, its spread (the published distribution, where a maker or standard gives one; most makers publish none), and where that size lands on the reference scale, a shared yardstick for reading grit numbers across makers.
A-standard: SEM measures the abrasive (radiolaria silica) at ~3 micron across Asagi/Kiita/Karasu/Uchigoumori; it does not break down in use (clay is binder only).