Those stones Amakusa stones come from a quarry on the island Shimoshima, in the prefecture of Kumamoto. They are a beautiful natural stone and very fine.
This item from Amakusa has two types the red color and comes with #500/#800 grit and the other one is white color that comes with #1000/#2000 grit
Red Amakusa
Length:205 mm Height:75 mm Width: 43mm Weight: around 2KG
White Amakusa
Length:200 mm Height:70 mm Width: 40mm Weight: around 1.2KG
