Not all color diamonds are created the way that nature intended. Diamonds can be treated in order to develop colors that mimic the colors of natural stones, though artificial versions are not considered as rare or valuable.
Treated diamonds are not considered to be as good an investment as natural ones. Also, colors created through treatment can change over time. That is why it is important to get a certificate from a reputable laboratory (such as the GIA, EGL and IGI) that clearly identifies the origin of the stone and the origin of its color.
Many treatments can change the color of a diamond. Among the most common are using HPHT (high pressure, high temperature), CVD (chemical vapor deposition), irradiation, surface coating, and heat treatment. Each of these methods can be identified by a reputable gem laboratory such as the Gemological Institute of America (GIA), the European Gemological Laboratory (EGL) or the Independent Gemological Institute (IGI). If a diamond is artificially colored, the lab report will indicate "Treated" and identify the type of detected treatment used to alter its appearance.
