|This article is about a/an Precious in GoGo Sentai Boukenger.|
The Aqua Crystal (アクアクリスタル Akua Kurisutaru) was a crystal that was used to sustain the water levels of an underwater city where an entire civilization existed. After the crystal was mysteriously taken away, the water dried up and the city eventually became covered by sand, as if vanished into a desert. The only known clue to the crystal's existence was a scroll found by a college professor written in an unknown ancient language. The Boukengers attempted to get the scroll, but it was torn apart in a battle with two Jaryuu, Naga and Ragi, which ultimately left them with the important piece with the location. Ragi pursued the Boukengers and got his hands on the missing piece, but it dissolved in his hands when trying to hold it. Ultimately when with Akashi, Ragi revealed that he was actually a member of the civilization in search of the crystal in order to restore his home and fulfill a dream of his father, yet was forced to abandon his people and become a Jaryuu just to live on the surface. Using the scroll and the destroyed piece memorized by Akashi, the duo tracked the crystal down to the interior of a volcano, which they retrieved with SGS's new GoGo Jet vehicle and used to finally restore the underwater city to it's former glory. As a final reward, Ragi was able to return home with a repaired crystal of his father's allowing him to enter (due to destroying his own in order to search the surface world).