The Crystal King is a treasure in Pikmin 2 that is actually quartz crystal. It is found on 4th sublevel of the Bulblax Kingdom, where it is held by an Iridescent Glint Beetle. It is the 52th treasure on the List of Pikmin 2 treasures.
Captain Olimar's Journal
"At first glance, this may look like just a pebble, but it's actually a crystallized life-form! ...OK, so I don't have any proof. But it's still an exciting scientific discovery."
"Collectors of the rare, assemble! This is a one-of-a-kind specimen of a unique crystal life-form. Proof? True collectors need no proof. This romantic piece could be yours today!"