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 ruby celtic knot combines these concepts with the spiritual attributes of the lab ruby . Lab Ruby Is known As the gem of passion and desire and is the birthstone for the month of July. All of the items below are available in 14K white gold, 14K rose gold, and 14K yellow gold.