recycled

[Sky]

from the Chenthya Queendom (some spoilers ahead)

In Kikonokian culture (which includes the Chenthya Queendom, among many other tribes--though not all of mine follow this culture) gems are deposited near sleeping nichelings in the night by the mysterious goddess Sprigflower. When they wake up, they find their new gem and have the urge to press it to their chest, where it fuses with their skin, becoming a part of them. Their gems function as a meter of how much energy they have left before they're so tired that they fall asleep on the spot.

Gems that are ready to be replaced (usually for a color swap) or whose owner died will fall off and be gone by morning, presumably taken by Sprigflower.

Poor Onoko has passed, but his gem will be recycled as his nephew Chèèpi's third gem.