The celtic knot is an ancient symbol of the journey of life. With no beginning and no end, the knot represents the timeless nature of our spirits and the world we live in. A Aquamarine celtic knot combines these concepts with the spiritual attributes of the Aquamarine . A long time favorite of jewelry designers, aquamarine is the birthstone of March. The diamond-like brilliance of an aquamarine ring is sure to attract attention. Sapphire is the birthstone of September, and one of the most popular gemstones on the jewelry scene today. The deep blue color of a sapphire ring is just right for an evening out.