Star Platinum

Star Platinum is the Stand of Jotaro Kujo.

Jotaro awakens Star Platinum after DIO awakens his Stand due to their psychic connection. Jotaro uses Star Platinum to throw insanely fast and powerful punches.

At the end of Part 3, Star Platinum unlocks the time stop ability known as Star Platinum: The World, which follows the same rules as DIO's The World.

Appearance
Star Platinum is a muscular built looking dude with purple skin. He's got long black flowing hair and looks like a dude.

Powers and Abilities
Star Platinum is a close-range Stand with a range of two meters.

With his Stand, he is able to throw incredibly fast punches. Star Platinum is known for its speed, which allows him to take hold of bullets that get shot at him point blank.

At the end of Part 3, Jotaro realizes that Star Platinum and DIO's Stand, The World, are the same type of Stand, meaning that Star Platinum has the ability to temporarily stop time.

Trivia

 * Some people theorize that Star Platinum may be the spirit of Jonathan Joestar helping out his great-great-great grandson in battle due to his design slightly resembling him.
 * This is the first Stand to follow along with a naming-scheme that the next JoJo's Stands all follow, that being being named after a material. In this case, it's platinum.