Throughout history amethyst has been used to guard against drunkenness and is thought to be helpful in overcoming addiction. It has been used for hearing disorders, insomnia, headaches and other pain. Some sources suggest it is used to stabilize mental disorders.

Worn to make the wearer gentle and amiable. Amethyst powers include: dreams, healing, peace, love, spiritual upliftment, courage,  psychism, protection against thieves, and happiness....This is my birthstone...dorothy
http://www.bernardine.com/gemstones/amethyst.htm