Synthetic abrasives of this quality are now uncommon -- and at this price per weight possibly non existent. The sample in the photo below has been used (dry!) for pre-peening treatment of over 300 new scythe blades and the shaping of the odd ax, drawknife, hoe and knife (altogether the amount of abrasive work which would have long transformed several of the superstores' China or India-made bench stones into dust).

All in all, from the abrasives offered in our catalogue this is the one which for a dollar invested can remove more metal than any other. In its rightful domain (50RC or less) a good file is the king of hand-powered steel removal -- that is, faster than other hand-held stones, be they natural or synthetic. But for working marginally hard material you would wear out many files in lieu of a high quality carborundum stone. And, there are also jobs at which files of even reputable brand names (unless they are the very expensive titanium versions) are rather useless. Try to file, for instance, a good quality meat grinder knife, and you will accomplish nothing... This stone can sharpen it just fine.