Agate is also known as chalcedony quartz and comes in many colours and varieties. It is used to harmonize Yin and Yang, help build self-confidence, enhance mental function and strengthen the body/mind. Agate is a good protective energy stone and also helps the body connection to the earth. It is considered a good luck stone and enhances creativity and stimulates the intellect.
Beautiful and useful too! Pendulums are used much the same way as applied kinesiology or muscle testing to help determine the answer to a question.