In March 2013, researchers from China's Zhejiang University developed the world's lightest material ever made, Graphene Aerogel, is made from freeze-dried carbon and graphene oxide. Today it was reported that that bit of Graphene Aerogel was sold in an auction in China for 10 million yuan ($1.6 million).

http://www.graphene-info.com/original-graphene-aerogel-sample-sold-auction-16-million