The Time Stone,  one of the Infinity Stones, is a remanent of a singularity that predated the universe, representing the element of time. It's a green gem that was kept inside the Eye of Agamotto and placed under the protection of Doctor Strange. It has the capability to let the user bend and control time, and can create paradoxes and time loops if used wrong. 

If you attempt to touch the Time Stone for the first time, it will have to succeed on a DC 30 Charisma saving throw. On a successful save, you takes 5d12 force damage, but can now touch the Time Stone without taking damage. On a failed save, you take 10d12 force damage, and are magically placed in a different time period. (The time period is the DM's choice.)

You don't need to be holding the Time Stone directly to use it. If you have a powerful container to hold it in, like the Eye of Agamotto, you can use it without taking any damage.

Total Time Control. If you have the Time Stone, (You don't need to attune to it) you can cast Wish at a cantrip without taking damage, your Strength score going down, or never being able to cast Wish again AS LONG AS the Wish has something to do with time. 

You can cast Wish as a cantrip to do things like this: 

-Banish someone to a different time period

-Changing an item to a state is was or will be (Like removing a bite from an apple, or making a fresh apple rot)

-Travel to a different time

But, beware: If you use this ability, the DM can make it so you accidentally create a time paradox, putting anything from an apple or the whole multiverse into a whole infinite loop!

Destroying the Time Stone. The only way to destroy the Infinity Stones is preforming a Infinity Snap to destroy the Infinity Stones with a fully filled Infinity Gauntlet, destroying the Infinity Gauntlet and all the Infinity Stone attached to it. The creature wearing the Infinity Gauntlet  while preforming the Infinity Snap takes 12d20 radiant damage. It's impossible to destroy just one of the Infinity Stones with an Infinity Snap, because the blast would destroy all the stone as they are right next to each other on the Infinity Gauntlet.

Notes: Infinity Stone