The Infinity Gems are a set of near-infinitely powerful artifacts in the Marvel universe. The blue Mind Gem grants its user incredible psionic power, reinforcing any existing psychic abilities they may possess. Its wielder can to pour through the thoughts and dreams of of others, and form mental bonds that transcend any distance. In conjunction with the other gems, it can allow access to every mind in the universe at the same time!
The Elder of the Universe known as the Grandmaster was one of the earliest owners of the Mind Gem, since then it has passed through the hands of Moondragon, Professor X, Ms. Marvel and Beast.
The power set provided below will allow you to use the Mind Gem in your Marvel Heroic Roleplaying game.
Further Reading: Infinity Gems on Wikipedia, Infinity Gems on Marvel Database, Mind Gem on Marvel Database