Belgian Blue Whetstones (BBW) are used for finish or pre-finish sharpening on KME or Hapstone knife sharpeners.
Belgian Blue Whetstone is mined in the Ardennes mountains in Belgium. BBW is natural slate with a high garnet content.
BBW stones are universal, and can be used to sharpen knives of any steel.
Belgian Blue Whetstones should be used with water. All that is required is to wet the BBW surface. There is no need to immerse the stone. During the sharpening, slurry with garnets are released from the BBW surface. The more garnets are released, the more abrasive the grinding compound becomes. Try to keep slurry on stone surface.
BBW stones do not have any minor defects. BBW stones always have a color pattern; this is not a defect.
BBW stone does not require any preparations. It is naturally lapped to extra-fine grit.
Grit terminology is not applicable to natural sharpening stones, including slates. The behavior of a natural stone depends on its density and how good it was lapped. However, experts estimate BBW as 3000 - 4000 JIS.