You can create a magic link between your ioun heart and an ioun stone in your possession.
For as long as you gain the benefits of the linked stone, any numerical bonuses and penalties granted by the stone are increased by 1. You can maintain a link with only one ioun stone at a time. Creating a link to a new stone ends any previous links.
Pathfinder Player Companion: Heroes of Golarion © 2019, Paizo Inc.; Authors: Saif Ansari, Alexander Augunas, Mara Lynn Butler, Michelle Jones, Avi Kool, and Alex Riggs.