This stone has been believed to prevent drunkenness and have the power to quell a range of other physical appetites and indulgences. This sobering effect is also believed to clarify mental understanding, improving the decision-making ability of those who wear it. This made it a popular choice for giving to young men--helping them avoid temptation and keeping them clear-minded when using weapons. Leonardo Da Vinci once wrote that amethyst can dissipate evil thoughts and quicken one's intelligence. Healers have used amethyst to increase their psychic abilities and intuition for centuries. Cross-culturally, this popular gemstone was used as a symbol of peace and unification. It is also thought to evoke feelings of serenity and calmness in those who wear it. Amethyst is often used during meditation to provide an overall sense of spiritual balance. Some naturopaths use it to help treat insomnia, sugar imbalances, and headaches.