lead v. graphite
Sunday, December 20, 2009 Lead (atomic symbol Pb, atomic number 82) is a soft, malleable metal that turns grey when tarnished. Lead is used in lead-acid batteries, radiation shields, solder, bullets, and paint, among other things. Graphite is a soft, grey allotrope of carbon (atomic symbol C, atomic number 6). Lead is a neurotoxin that can accumulate in the body; graphite is harmless when consumed.
The ancient Egyptians and Romans used a thin lead stick called a stylus to draw on papyrus. Graphite is, and always has been, the substance in the core of wooden pencils. At some point prior to 1565, the world’s only known large deposit of graphite was discovered in Cumbria, England, ensuring England’s monopoly on pencil production for many years. At the time, the Cumbrian mineral was thought to be a form of lead, and was called plumbago, which is Latin for ‘lead ore’. This misconception has persisted to the present, which is why pencil graphite is still called lead.
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