Today, Patrick Charton of the French nuclear waste management agency ANDRA presented one possible solution to the problem: a sapphire disk inside which information is engraved using platinum. The prototype shown costs €25,000 to make, but Charton says it will survive for a million years. The aim, Charton told the Euroscience Open Forum here, is to provide "information for future archaeologists." But, he concedes: "We have no idea what language to write it in."
http://news.sciencemag.org/sciencenow/2012/07/a-million-year-hard-disk.html?ref=hp