Crystals

 are a substance found only deep, underneath a layer of granite, and are composed of unknown elements. Its crystalline structure is useful in advanced composites.

Location
 are found only deep underground in the Crystal Caverns. Among the caves there are deposits of Light Crystals, Black Crystals, and extremely dangerous monsters such as the Armored Ant and Acid Ant.

Properties
 have a rhomboidal-lattice structure that gives them incredible strength. The  grow upon contact with water.