Show students a chunk of graphite from an old historic mine in New Hampshire. They will be fascinated with the idea of writing with a piece of mineral. Use a battery, wire, and bulb to show that graphite conducts electricity. Each sample is about one pound of graphite and may contain some rock matrix.Graphite from President Pierce's mine was used to make pencils in the 19th century. In 1849 the mine produced twenty tons of graphite per year at 3 to 5 cents per pound or about $1600 per year.