Elemental Fairies of the Periodic Table: Lithium

Element number three, Lithium, was first found in rock, and, after a bit of coaxing, revealed herself to be a metal so light she can float on oil.  Very pale and delicate, scratches easily, is often seen clad in black, because she is moody and reacts easily to her surroundings, but when burned, she glows rose red.  She is very energetic for her diminutive mass, so she makes a good electrical battery.  She might seem frightening to some, but she tries hard to maintain a delicate balance within herself, to keep her moods under control, and has even been employed as a medicine that helps some people do the same.
(I have been dawdling on this one for nearly two years!  Sorry it's out of order, but I was bribed to get this one done early and Helium will be finished afterwards.)