How to evaluate the color of the diamond

Although most diamonds are Yuanse glance, but, since diamonds deep in the earth system, high temperature and high pressure crystallization from government, so often contain diamonds are a number of other micro-elements, so that the diamond has had the same degree of different shades of colors. Diamonds are often seen near Yuanse or yellow, slightly, saying that the Cape series, the color of these diamonds is due to micro-diamond containing nitrogen is the element, the further off the S & P series of diamond grading, the only effective approach is unknown diamonds and a set of criteria to compare the diamond to determine its color grade.