It may be possible to use the stone you have for some of the work but the sear work is normally done with a hard Arkansas stone. The four grades of these stones are Washita, soft Arkansas, hard Arkansas, and Black hard Arkansas... Hard Arkansas at least is the prefered stone for polishing sears and I really prefer the hard Black stones.. The object of stoning is to polish the engagement surfaces only removing very little metal.. I have heard opf people even using sand paper for some such work but the shapes needed are hard to develope using sandpaper even though super fine grits sizes are available.. I now use a set of ceramic stones from Brownells. They cut really well and leave a polished surface behind.. and they are flat.... When I started smithing I used India stones in very fine grades to polish sears. All stones are grades ropughly the same , grit size or cut and hardness and of course the material they are made of.. All the Arkansas stones are made of the same material.. The grit size gives an indication of the level of finish that can be developed with that particular stone. Hardness, gives an indication of the hardness of the material that can be worked on that stone while retaining the shape of the stone. The harder the stone the finer the angles that can be done with confidence. An engraver sharpens the very hard gravers he uses to cut hardened steel with using a synthetic ruby stone. These are sort of the nea plus ultra of the stone world. Ruby is very hard and almost never needs flattening unlike carbarendum(sp.) which gets swaybacked pretty quickly,.. Hope I've helped a bit.
