The principal thing in polishing stalactites and small stones after they are cut is to grade the hardness of the polishing material with the stone to be polished. For cutting a surface level, use various grades of emery on lead laps, with a separate lap for each grade of emery. See that all scratches are removed. For the polishing, on hard wood that will not warp glue a piece of buff leather. On this place a little putty powder, which, like the emery, must be used wet.

The following has been given as best for soft stones: - Take, say, 1/2 lb. of putty powder, put it in a jar, cover it with nitric acid, and place it in the open air, as the fumes are noxious; let it stand for a day, then pour off acid and water repeatedly until the water ceases to be acid. Polish with the residue.