What is the blue light emitted by Loki's scepter? Is it the same light that the Cube emits? Does Thor have something with a similar light or is it something that Loki gets from the "Ice People"?
Whilst on the helicarrier and examining the sceptre, either Stark or Banner (I forget which) comments that it is powered by the Tesseract.
Actually it is not. In fact, they assumed it was the Tesseract because they do not have enough details to see if it was from anything else. The stone is actually the mind gem. I know there's a whole hoopla of gems that belong to the Infinity Gauntlet. It is in fact the mind gem because that gave him the power to control people's minds!