Holy Night Snow Six-Star Evolve Gem

The gem with the purest power of the Astral can Evolve Senshi "Holy Night Snow Yui" to a higher star level.
It can be given to Senshi through the "Give Gift" button in the Senshi interface, and can increase the star level up to Six-Star.
You must own a One-Star Senshi before you can give the gift, and you can only increase one star level at a time. After Evolving, the existing star energy will reset to zero.