Re: Thanos and Loki
It's not the Mind Gem. It was said so in the movie and the music used when it was used, and the way the energy looks, is reminiscent of the Tesseract. I'm certain an Infinity Gem is on Earth anyway, and Thanos sends an army (Skrulls?) to go get it, and if SHIELD don't give it up they'll destroy the planet.
Avengers 2 is gonna be so ****ing awesome.