Mana Extract

"A magical 'sap" that can be found on the surface of giant trees that are hundreds of years old. It is named for its appearance the location where it is found, but strictly speaking, it is not actually tree sap. Rather, it Is the liquid product of cross-contact between the Wind Fairy and Earth Fairy. As such, it is seldom found in the wild, and most of It is harvested by forest-dwelling races, so humans are rarely able to obtain it."