Lead

Lead is a soft, dense, dull-gray metal that people have mined and smelted for thousands of years. It comes mainly from the mineral galena (lead sulfide), and much of today's supply is recycled from old batteries. Its symbol, Pb, comes from the Latin plumbum, which also gave us the word plumbing, since the Romans made water pipes from it.

Today most lead goes into car batteries, and its density makes it a good shield against X-rays. For decades electronics were joined with tin-lead solder, but lead is toxic, especially to children's developing brains. Since 2006, European rules have pushed electronics to lead-free solder, mostly tin with a little silver and copper. Lead is the heaviest element with stable isotopes.