Originally Posted by
alx
Most if not all hones/sharpening stones have some form of silica as the cutting particle, and a type of silica called chert is the one you are looking for especially the form called radiolarians. Radiolaria are the silica based shell casing of a prehistoric sea animal, it is still silica but its a very fine particle form of silica. Arkansas stones are chert but of a monolithic form, all solidly bound, Japanese naturals have chert particles that are individual and mixed in with clays to created a chert grit particle that acts and cleaves as it cuts. You can search geology maps in your area for ancient sea beds that are rich in radiolaria. Just one idea.
Alx