Glimmerkin eggs glow a pale white when touched by moonlight. As the egg nears hatching the heart will begin to glow as well, even when not under the moonlight.
Glimmerkins are imbued with a magic that is strongly tied to the moon. These powers begin to develop as the Glimmerkin grows out of its kitten phase. Around this time Glimmerkins become bonded with a type of sprite, the ultimate source of the Glimmerkin's magical abilities. Glimmerkins must learn to trust the sprite as well as protect it, as the sprite can not use any magic on its own, it can only share magic with others. This symbiotic relationship eventually results in a more permanent bonding as the two will fuse together to transform into a fully fledged Glimmerkin, one with complete mastery over their unique magics.
Glimmerkin's who are unable to protect their sprite are never able to reach their full potential. These magically stunted Glimmerkin's live out rather mundane lives and must seek out protection from other more powerful beings in order to survive in Fairy World.