The disadvantages of graphite electrodes are as follows: a) low current density, b) high contact resistance, c) low oxidation temperature, and d) nonwetting. Graphite mining in Sri Lanka has occurred since the Dutch occupation of the country. It is the only country in the world to produce the purest form of graphite, vein graphite (also known as lump graphite), in commercial quantities, which currently accounts for less than 1% of the world's graphite production. Excessive exposure to graphite presents serious dangers to the respiratory system. Well-documented health effects include lung fibrosis and pneumoconiosis, an occupational lung disease. Pencils do the same thing: once they breach the epidermal layer of the skin, they leave behind their "ink," which is graphite particles, in the dermis, where they remain undisturbed and unabsorbed by the skin. Current production methods of graphene, both top-down and bottom-up, are expensive, energy and resource intensive, and simply produce too little product, too slowly—graphene's Usage for Radiation Shielding. One of the carbon's special forms, graphene, comes in the weak radiation absorber category because of the low value of atomic number it possesses, Z=6, which is nothing to be surprised by, as its thickness is of only one layer of atoms. Here's a myth, buster: There is no lead in pencils. Rather, the core is made up of a non-toxic mineral called graphite. The common name "pencil lead" is due to a historic association with the stylus made of lead in ancient Roman times. Graphite is soft and slippery because it has a layered structure, because of which they could slide over each other. The bond is broken easily because of the weak force of attraction, so they slide over each other. If you are looking for high quality, high purity, and cost-effective graphite, or if you require the latest price, please email contact mis-asia.