Re: Captain America 2: News and Speculation - Part 14
Loki's spear's gem has not been confirmed to be one of the infinity stones.
The only 2 that are known of so far are the Tesseract and the Aether.
"A shared universe, like any fictional construct, hinges on suspension of disbelief. When continuity is tossed away, it tatters the construct. Undermines it."
-- Peter David