From the Super Mario Wiki
Retrieved from "https://www.mariowiki.com/index.php?title=Purity_Heart&oldid=2426513"
The Purity Heart was an artifact created by the Tribe of Ancients in Super Paper Mario in order to counteract the Chaos Heart. According to Merlumina, the Purity Heart was divided into the eight Pure Hearts in order to protect them from evil. Once the four heroes collected all the Pure Hearts, they would combine to make the Purity Heart, thus shattering the Chaos Heart and stopping the Void; the last time the Purity Heart was used, it also unintentionally killed what little remained of Dimentio, who had left behind a shadow of his power to prevent the Chaos Heart's disappearance after his final defeat as Super Dimentio.
It can be seen at the end of the game twice: first when Tippi takes the revitalized Pure Hearts to Mario, Peach and Bowser during the Dimentio fight and they all converge on her, and also when Tippi and Count Bleck get married to stop the Void, when all the Pure Hearts join together. It is then revealed to be a golden color.