Originally Posted by
Iceni
It depends on the local rocks.
Naturals that are common worldwide have a few factors in common. They were better than anything in your local area, Faster, smoother ect. Someone was digging them up and selling them on a commercial scale, And the price of a bought hone was cheaper then the time invested in looking for material and cutting it yourself.
Provided you have time to go looking, and then time again to make a rock into a hone shaped object then you are at least on the right track. Not all rock is equal, and if there was anything of commercial value about in large quantities someone at some point will have tried to sell it, So look for old document in your area and see if there are any mines locally that were used for hones or that made a side business out of hones. Provided you live in an area that was populated more than 100 years ago someone will have gone looking and if there is anything to be found they would have found it.
The UK is fortunate in it's geology that in a small area we have lots of different era's and grades of rocks. This gives a great scope to go looking for new stuff, If where you live is more uniform then you may have to travel some distance to fine suitable base materials.
Scandinavia produces a lot of Schists. And those are common stones to be found as sharpening stones for swords and axes across the Viking world. They transported the stone across huge distances to Iceland, Britain, France. And while local stones were available the demand for that stone is seen through the Viking era almost like a secondary currency.