From the Crystalvaults.com site:

Amethyst is a wonderful talisman for use in the creative arts, especially in darker shades. It assists endeavors where new, original results need to be created using tools and methods of the past. It is often used as the Artist’s Stone, the Composer’s Stone, the Inventor’s, Poet’s and Painter’s Stones. Keep an Amethyst crystal or cluster in the area to focus and amplify the creative elements of the Universal Life Force.

Called the “All-healer,” Amethyst is one of the most effective crystals for healing people, plants and animals. Natural unpolished Amethysts or geodes are particularly helpful placed where plants will not grow or animals refuse to sit. It also counteracts negative earth energies beneath buildings or anywhere that feels hostile. [Eason, 212][Hall, 54]

Amethyst protects against psychic attack, paranormal harm or ill-wishing, and returns the energy back to the universe after being transformed into positive, loving energy. To increase this power and attract good luck, draw an image of the sun and the crescent moon over an Amethyst in lavender incense smoke. [Melody, 110][Eason, 212]

Referred to as “nature’s tranquilizer,” Amethyst calms and soothes, assisting the transmission of neural signals through the brain. It relieves obsessive compulsive disorder and hyperactivity in children and animals. Place under the pillow or mattress, or rub the center of the forehead counter-clockwise to cure insomnia and stimulate pleasant dreams. It is especially effective for children’s recurring nightmares and fears of the dark, and may help alleviate homesickness. [Eason, 212][Hall, 54][Megemont, 25]

Amethyst is an excellent stone for diplomats, negotiators and business people. It calms angry temperaments and gives a distinct advantage in situations where debating is required. Wear or hold Amethyst to bring in spiritual insights coupled with intellectual reasoning. [Megemont, 26][Melody, 111] As a luck and prosperity crystal, Amethyst is good for reducing the tendency to overspend, gambling addictions or unwise investments. [Eason, 44]

Amethyst is connected to the Temperance card in the tarot, representing balance. It is a stone dedicated to curbing overindulgence and bad habits, and is an excellent aid to quitting smoking, drinking and drug use, as well as unhealthy physical passion. It also provides the strength needed to obtain freedom from addictive personalities, one’s own or another’s. Placing an Amethyst on the navel is believed to protect a person from intoxication, and in conjunction with other treatments such as counseling, helps cure addictions. A naval piercing makes it possible to always keep an Amethyst in this spot. [Megemont, 25][Simmons, 28][Melody, 110]

Amethyst is the stone of St. Valentine and of faithful lovers because St. Valentine was thought to have worn an Amethyst ring engraved with the image of Cupid. It is also referred to as the “couple’s stone” and gives meaning to relationships that over time, transcends the carnal union and gives way to deeper connection and a more soulful communion. Wear as an engagement or eternity ring for fidelity, or as a locket to call back lost love. [Eason, 212][Megemont, 25]

Amethyst Physical Healing Energy

Amethyst boosts the production of hormones, and stimulates the sympathetic nervous system and endocrine glands to optimum performance. It supports oxygenation in the blood, and aids in treatments of the digestive tract, heart, stomach, and skin. Amethyst also strengthens the immune system and reduces bruising, pain and swellings. It has been used with excellent results as an elixir in the treatment of arthritis. [Melody, 111][Hall, 55][Gienger, 13]

Amethyst is thought to relieve the symptoms of tinnitus and other hearing disorders, and is highly beneficial in treating insomnia, especially when caused by an overactive mind. It is calming and soothing to the neural impulses in the brain. Its energy ameliorates the pain of headaches and migraines, and reduces stress and nervous tension. It may be used to treat psychic disturbances and to stabilize brain imbalances, but should not be used in cases of paranoia or schizophrenia. [Hall, 54-55][Melody, 111][Megemont, 25][Ahsian, 30]

Amethyst Emotional Healing Energy

Amethyst is especially supportive of the emotional body, bringing those who are overworked, overstressed, or overwhelmed back to center. It eases the mental anxieties that lead to physical tension and headaches, and is a great crystal to calm those who tend to be hot-headed and easily angered. [Raphaell, 80][Gienger, 13]

Amethyst helps in identifying the root causes behind one’s negative behaviors, habits and emotional patterns that create imbalance and disease. It also helps one understand the reality of cause and effect in behavior, and assists in better decision making. Amethyst is a marvelous aid in overcoming addictions by counteracting the effects of drugs and alcohol on brain function, while imparting its own peaceful sustaining energy. [Ahsian, 29][Hall, 54]

Because Amethyst initiates wisdom and greater understanding, it is a comforting crystal for those grieving the loss of a loved one. Its presence communicates that there is no death, only transitioning and changing of forms. It encourages the release of sorrow, and rejoicing in a loved one’s spirit being freed from the confinement of the physical body. Called “the soul stone,” Amethyst assists in understanding and connecting to the eternal existence of the soul and initiates one’s own deep soul experiences. It is an ideal crystal to hold or meditate upon during the death experience, of another or oneself, allowing the release of the temporal physical body with more ease, assuredness and peace. It is a perfect stone to gift to those with terminal illnesses or to use in preparation for a conscious death experience. [Raphaell, 80][Gienger, 13]