A Correction

So, it seems I was wrong about something. The Unobtainium in Avatar is not, as I had thought, a substance that grants anti-gravity; the floating rocks and several reviews misled me. Turns out the floating rocks are being magnetically levitated, not gravitationally—the unobtainium is actually a natural superconductor (indeed, apparently, a hot one), which makes it useful in producing the magnetic fields necessary for directing the thrust of most advanced spacecraft engines.

This is slightly encouraging—it's a boatload harder than I'd thought it was, though, as I said, they could've gone with the anti-gravity idea by the simple expedient of saying the rocks have magnetic monopoles in them. It does, however, carry with it its own difficulties; naturally occurring hot superconductors are...unlikely, to put it mildly, since they're usually compounds whose structures look like this and often have things like Yttrium in them. Also, large veins of a natural superconductor would probably make Pandora's electric field merry hell to have to deal with.

Still, "superconductors for the rocket thrust" is something I'd like to hear more often in SF movies, so I salute the writers for it.

Now if the biology, sociology, politics, economics, and don't let's forget writing of the movie didn't suck out loud, we'd be in business.