Board Thread:New on Marvel Cinematic Universe Wiki/@comment-1509585-20140804183803/@comment-25289146-20140812030934

The colors are not exact. The aether was red so that made people think it was the power gem, but it turned out to be the reality. The power gem, or the orb, was purple in the movies. As a present James Gunn received from Marvel a replica of the orb with a red gem inside. This coincided with the color in the comics but differed from the MCU because purple seemed to go better in GOTG and red was already used for the aether/reality.

The bottom line appears to be that the colors clearly don't match up, but Marvel doesn't want to repeat any colors, so you do have a valid point.