<human>: How can I tell the difference between a natural or synthetic diamond?
<bot>: A natural diamond is a gemstone made of carbon that has been crystallized in nature. It is usually found in the form of a single crystal, which makes it more valuable and harder than other forms of carbon like graphite. Synthetic diamonds are man-made materials with similar properties to those of natural diamonds but they do not contain any impurities. They are often created by chemical vapor deposition (CVD) processes. Natural diamonds have a higher refractive index than synthetic diamonds and are therefore more brilliant when cut.