Confirmed:
- Space Stone: Blue: Tesseract
- Power Stone: Purple: The Orb
- Mind Stone: Yellow: Chitauri Scepter
- ? Stone: Red: Aether
Speculation:
- Reality Stone: Aether. A lot of people thought it was Power until recent reports for Guardians of the Galaxy confirmed that the Orb was in fact the Power Stone, that makes Reality the next most logical choice as Malekith wanted to use the Stone to alter reality, reverting the Universe back to darkness.
That leaves the Time Stone and the Soul Stone. Do you think we've already seen them in the MCU or are they going to show up in other films?