Fancy coloured diamonds are not always "natural." Their Colour may have been modified or enhanced through one or more processes involving irradiation and/or extreme heat known as High Pressure High Temperature (HPHT) treatments. This process creates yet artificial Colours from low grade diamonds to improve their value. The only way you can be sure that you have purchased a natural fancy coloured diamond is by the certification it comes with. The following certification providers are the only laboratories endorsed by Leonard's Diamond and Gold to guarantee your purchase.