Blue Crystal

A Blue Crystal has the ability to drain a water-logged area in order for you to pass through an area. It also has the same ability as the White Crystal, which allows you to see invisible platforms. In order to obtain a Blue Crystal, you must first have bought a White Crystal from a merchant in the town of Jova and then trade that crystal for a Blue Crystal from a Crystal Trader in the town of Aljiba.

The only water logged area that this item can help you get through is Yuba Lake, which is at the end of the Lower Road to the east of the Aljiba Woods. Pressing down for a few seconds will cause the water to drain, and the path to Rover Mansion will be accessible.

This item can be traded up for a Red Crystal from a Crystal Trader from the town of Aldora, which has all the abilities of the White Crystal and the Blue Crystal, plus the ability to summon a transportation tornado at a certain location. The Red Crystal's water drain location can also help you get to another area later in the game.