From another site:

Lepidolite: A purple Lithium containing Mica stone ( and/or visa versa). Lithium is used extensively in psychiatric medicine for it's calming properties and particularly for treating Bipolar disorder. In Crystal Healing Lepidolite is a powerful and effective anti anxiety stone and will help reduce symptoms of Post Traumatic Stress and decrease anger and depression.

I think that it would be pretty cool to wear Lithium around my neck. It can be my own private reminder that I am working hard to heal myself, and others can admire it too. Maybe if I have a really bad day, I can lick it, ha ha ha.