The Infinity Stones are six immensely powerful objects tied to different aspects of the universe, created by the Cosmic Entities. Each of the stones possess unique capabilities that have been enhanced and altered by various alien civilisations for millennia.
Only beings of immense power can directly wield the Stones, such as Celestials, or the Mad Titan Thanos. Lesser beings face dire consequences: Jane Foster became ill after being exposed to the Aether and Carina exploded when she touched the Power Stone; however, these effects can be reduced if a group is sharing the power among themselves.
It is also possible to place an Infinity Stone inside a container to prevent a person from directly touching it, allowing the user to wield the Stone's power without suffering the normal repercussions. Examples include the Space Stone inside the Tesseract, the Mind Stone inside the Scepter, the Power Stone inside the Cosmi-Rod, the Time Stone inside the Eye of Agamotto, and all the Infinity Stones inside the Infinity Gauntlet.