Diamond stones are worth the money you spend on them. I you sharpen your chisels and gouges on a regular basis the time saved by using diamond stones is way worth the cost. I have the stones offered by Woodcraft. They are about 2” wide by 5” long by 3/8” thick. I have the extra fine, fine and the fine and corse and the fine and extra course stones. These three handle the bulk of my sharpening work. I also have a 12000 grit stone that will put a mirror polish on a chisel and a ceramic stone but I don’t use these except on special occasions. I have been using these stones on a daily basis for about 10 years and they still cut quickly. I would never go back to regular stones. Regular stones work, it just takes a lot more time to get the job done. I think I have about $160 dollars in my stones, again worth every penny.