This amethyst from India is mainly of the darker variety and the stones are smaller than regular amethyst stones. 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 overstressed mind.