Perhaps the best way of polishing cornelian stones in the rough is first to grind them level on a suitable stone, or on a piece of Yorkshire grit obtained from a tombstone cutter. The stone must be kept wet. When a level face is procured, grind out all the markings with emery powder, not too fine -, use this on a thick sheet of lead with water. On another sheet of lead grind with a finer emery all marks left by the first emery. Then grind with finest, emery on another sheet of lead; by this time there will be a dull polish. When no scratches are visible, polish with putty powder on a piece of felt or leather. Two things must be remembered: Do not stop grinding with one powder until all markings of a previous grinding are removed; and secondly, all the grindings must be wet.