SCIENCE - Ancient Roman Metal Used for Physics Experiments Ignites Science Feud

Archaeologists and physicists are at loggerheads over ancient Roman lead--a substance highly prized by both camps for sharply diverging reasons. Very old lead is pure, dense and much less radioactive than the newly mined metal, so it is ideal for shielding sensitive experiments that hunt for dark matter and other rare particles. But it is also has historical significance, and many archaeologists object to melting down 2,000-year-old Roman ingots ...

http://www.scientificamerican.com/article.cfm?id=ancient-roman-lead-ph