The Crystal Star was the second item that Usagi used to transform into Sailor Moon. It was also used to perform Moon Crystal Power on the Ayakashi Sisters and Black Lady.

In the anime, it was created when the Silver Crystal merged with her original transformation brooch. In the manga, Queen Serenity left it for Usagi in the Prayer Room, and Usagi found it when she visited the restored Moon Castle after the defeat of Queen Metalia. Usagi simply had to place the Silver Crystal inside the brooch in order to use it.