Poison Ring Large Smooth Round AmethystAmethyst stone in a roped setting on a sterling silver poison ring and band. Size 6. 75 Amethyst is believed to clarify mental acuity and improve decision making ability. Healers have used amethyst to increase their psychic abilities and intuition for centuries. It is also used as a symbol of peace and unification. and evokes feelings of serenity and calmness. Amethyst is often used during meditation to provide an overall sense of spiritual balance