Agate is a variety of silica, mainly chalcedony. Agate stones can be found in different types of rocks, especially volcanic rocks. It can be found mainly in Brazil, Argentina, Uruguay, Mexico, Australia, Botswana, and certain parts of the US, to list a few. One of the oldest of healing stones, agate is revered as a stone of strength, used in ancient civilizations, on the breastplates of armor to bring warriors courage and success in battle. Agates are very protective stones, making them the perfect stones for amulets and medicine bags. They also supply courage, emotional strength and self-confidence to the wearer.