The most expensive material on the planet earth is antimatter.It is worth a whopping $62.5 trillion per gram,yes you heard me right.Damn it !!

Scientists claim that antimatter is the costliest material to make.[42] In 2006, Gerald Smith estimated $250 million could produce 10 milligrams of positrons[43] (equivalent to $25 billion per gram); in 1999, NASA gave a figure of $62.5 trillion per gram of antihydrogen.[42] This is because production is difficult (only very few antiprotons are produced in reactions in particle accelerators), and because there is higher demand for other uses of particle accelerators. According to CERN, it has cost a few hundred million Swiss Francs to produce about 1 billionth of a gram (the amount used so far for particle/antiparticle collisions).[44]

Several studies funded by the NASA Institute for Advanced Concepts are exploring whether it might be possible to use magnetic scoops to collect the antimatter that occurs naturally in the Van Allen belt of the Earth, and ultimately, the belts of gas giants, like Jupiter, hopefully at a lower cost per gram.[45]

http://en.wikipedia.org/wiki/Antimatter

Very difficult to produce...

Wen i first saw d topic i was like wtf well in d future dat same antimatter may be sold less than 1million dollars per gram even better and efficient production dan d present ones been produced now.

mkmyers45: Very difficult to produce...

Yes,very difficult to produce.

ninja4life: Wen i first saw d topic i was like wtf well in d future dat same antimatter may be sold less than 1million dollars per gram even better and efficient production dan d present ones been produced now.

I don't think so because of it's vast usage especially in nuclear application.