In Ancient Egypt, the Mer-Ka-Ba was three words. Mer meant a kind of light that rotated within itself, Ka meant the human spirit, and Ba, the human body. So Merkaba means a rotating light that would take the spirit and the body from one world or form into another. It can be activated by meditation, with the breathe, and by changes in perception.
Amethyst is the purple variety of quartz crystal composed of silicon dioxide with traces of iron. Helpful in ridding nightmares. Just hold the Amethyst crystal on the forehead for a minute and ask it to guide you through a peaceful sleep, then place it under your pillow. Also helpful to calm an overworked and over stressed mind.