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 Lab Sapphire celtic knot combines these concepts with the spiritual attributes of the Lab Sapphire . A pair of sapphire earrings set in yellow or white gold is a classic, and is always appropriate. Choose from genuine sapphire, or the more affordable lab-created gem. A pair of sapphire earrings set in yellow or white gold is a classic, and is always appropriate. Choose from genuine sapphire, or the more affordable lab-created gem.