Charnley Forest Hones
Charnley Forest hones are very fine and quite hard. Some rate them at around 15k to 20k. They are very slow cutters, some suggesting as many as 100 to 200 laps to finish. Some highly recommend the use of oil, but not all oils are to be used, some are to be avoided.
They are often irregular in shape/cut. Their colouration varies. Commonly a green-grey with spots or streaks of red/pink/purple. Some are unfigured. To find a Charnley Forest hone in a simple wooden one-peice box with one-peice lid seems common, but other stones are also found in similar boxes.