Indonesian Natural Stone Red Medium Grit

Red is similar to a Red Amakusa or Natsuya stone and is approximately 1000 grit 

Medium:

200x50x30 mm
650 g

Large:

200x80x45 mm
1800 g

*Measurements are approximate.

These natural stones are quarried from volcanic tuff in West Java, Indonesia. Tuff is formed from silica rich volcanic ash that is fused into a solid stone in pyroclastic flows; essentially a mudslide of extremely hot volcanic gas and fine pulverized stone. If you have used Japanese Amakusa or Natsuya stones these are the same type of stone but  a little harder and often finer than Amakusa or Natsuya tuffs.

These stones have a homogenous grit structure and even hardness throughout the stone which makes for both an even scratch pattern and even wear during use and they go out of true very slowly.

The red stone will cut more aggressively by generating some slurry with a stone flattener and conversely cut a little finer used only with water and the smooth surface of the stone. 

These offer more than a new natural stone sharpening experience, for natural stone users these can be integrated into an all natural progression as they fill in for some commonly used grits or in between medium and fine stones or can be used on their own to make finer medium grit edges or toothy low fine edges.

Red is similar to a Red Amakusa or Natsuya stone and is approximately 1000 grit 

Black is in approximately the 2000 - 3000 range range and is a bit like a hard aoto stone or a harder, finer version of a Tsuchima nagura. It can be adjusted to cut more aggressive with slurry or a bit finer with only water.  

White is finer and and lands approximately in the 3000 - 4000 K range, it is a bright finish that cuts like a toothy fine stone but still has visible scratches and removes medium grit scratches well. It can be adjusted to cut more aggressive with slurry or a bit finer with only water.  

These grit estimates are based on entirely subjective judgment of comparing the cutting speed and scratch pattern of natural and synthetic Japanese stones, being natural stones they cannot be graded in the same way as synthetic stones which use a measurable industrial grit.