Montana Agate (USA) These beauties are found in Yellowstone River’s alluvial gavels. They were formed during the Pleistocene period. Montana Agate is believed to strengthen your self-control so that you will be able to stop unhealthy desires. You will also enjoy self-confidence and physical vitality because of your reduced stress levels. Montana Agate will promote good health and longevity. Montana Agate is believed to protect you from all kinds of harm. It will also infuse you with strong and calming energies. It will balance your yin and yang energies that will help you increase your good fortune. It will dispel the negative energies and help you keep in touch with reality. It also helps in sleeping problems.