Mind Gem

The Mind Stone, also referred to as the "Stone of the Mind", is a ficitional cosmic artifact featured in comic books published by Marvel Comics. It also appeared in the Marvel Cinematic Universe series of films.

The Mind Stone is one of five ancient items that comprise the Infinity Stones. In the Marvel Cinematic Universe, the Infinity Stones were created by the Celestials and contain great power. The Mind Stone, as its name implies, grants one the ability to affect the minds of others.

The Mind Stone was housed in the cradle of Loki's scepter. It was later used to help bring life to Ultron's creation, the Vision. The Vision has since become the guardian of the Mind Stone and wears it upon his brow.

Films

 * 1) Avengers, The - In Loki's scepter.
 * 2) Avengers: Age of Ultron
 * 3) Captain America: Civil War - On Vision's brow.