Cubic Zirconia is similar in appearance to natural diamonds, making it one of the most popular man-made stones. Natural and lab-grown diamonds are composed of carbon, while cubic Zirconia consists of zirconium dioxide (ZrO2). Cubic Zirconia can also occur in a variety of colors. These stones provide distinctive and affordable substitutes for fancy colored diamonds, or colored gemstones, such as emerald, ruby, and sapphire. If you're on a budget, cubic Zirconia will be a great, inexpensive option for your engagement ring, usually priced at less than $100.