You can refill them and I encourage you to do so. This video explains how to refill the pencil, complete with close-ups. Don't throw them away, refill them! Remember, the Paper-Mate Sharpwriter pencil uses 0.7mm lead. Standard Pentel lead will work excellent. The video was recorded with a Sony EVO-210 Video 8 8mm VCR.
Uses of Carbon. Carbon (in the form of coal, which is mainly carbon) is used as a fuel. Graphite is used for pencil tips, high temperature crucibles, dry cells, electrodes and as a lubricant. Diamonds are used in jewelry and â because they are so hard â in industry for cutting, drilling, grinding, and polishing.
Graphite usually occurs in flakes in metamorphosed rocks rich in carbon, but it can also be found in veins and in pegmatites. Where large deposits are found it is mined and used as an industrial lubricant and for 'lead' in pencils. The crystallinity depends on the temperature of formation and the grade of metamorphism.