Man-made Oilstones

The clever stuff - India sharpening stones are manufactured using a proprietary process that impregnates them with a petroleum based product that allows the lubrication used during the sharpening process to stay on the stone’s surface. As a result, the metal from the object being sharpened and small pieces of abrasive that break off the stone become suspended in the lubricant. This prevents these materials from imbedding into the sharpening stone’s surface, keeping it free cutting and making it easy to keep its surface clean.

With use, oilstones develop a concave wear pattern. To re-flatten, attach 120 grit waterproof sandpaper to a glass plate, wet, then 'sand' the stone until flat or use a flattening plate.