Everyone has off days. Maybe something happened to bring you down, or maybe the bad energy appears out of thin air. When one of these gloomy periods descend, you probably have some pick-me-ups in your back pocket — a good run, a favorite food, a talk with friends. And increasingly, people are turning to the power of crystals to lift their moods. Some even use healing crystals to address depression, though there's no medical evidence to back its effectiveness. Those suffering from depression should see a physician.