The 3 Pearls

A pearl is obviously a VERY import part to a diamonds reign. Red made many for herself, two of her own group solely for maintenance for the communication between her, and her sisters. The 3 depicted here are the 'core' three Pearls, and are all plastered all over homeworld as examples of what to be for other Pearls.
No one is quite sure what happened to reds pearl when she came home, all they knew is that she returned without her. Pink knows. But he is unaware of anything beyond his quarantined planet.