try a Jnat or Thuringians slurry and you will see amazing results, since the Garnets ( coticule cutting agent ) particles are to hard to break down or very slow to break
i just bought a set of 9 natural slurry stones and starting testing them last week, i shall post my findings sone :D
Attachment 196815
the nakayama one is a really fine one, but you need to wait for results.
thanks