There are 4 general ways to classify a diamond: Clarity, Color, Cut, and Carat. These are referred to as the 4 C's of diamonds and provide a standardized way of evaluating diamonds. Color, or the lack of, is an extremely important and often times incredibly diverse characteristic of diamonds. Diamonds come in a variety of colors. Among some of the natural colors found in diamonds are orange, grey, blue, red, and black.

Most of the time interstitial impurities or structural defects in the diamond are responsible for changes in color. The exception to this are diamonds that, when exposed to radiation, turn green in color. Pure diamonds are diamonds that are structurally and chemically untainted and are completely transparent. These types of diamonds are very rare and incredibly expensive.

Nitrogen impurity is the most common cause of color in a diamond. Often this leads to a yellow or brown diamond. In much rarer cases warping of a diamonds crystal's during the growth stage can cause the diamonds to exhibit pink, red, or brown colors.

In the early years of diamond grading there were many different and confusing methods of describing a diamonds color. The Gemological Institute of America (GIA) changed all of this when they developed the D-Z Grading Scale. The GIA, founded by Robert Shipley in 1931, is considered to be the world's chief authority in gemology. The D-Z scale put an end to many of the numerous terms that were developed to describe a diamonds color as well as many conflicting scales.

This scale assigns each diamond a character D-Z from the alphabet; hence it is called the D-Z Scale. Diamonds that are rated D-F are considered to be Colorless. These diamonds are extremely unusual and costly. Diamonds that are assigned a G-J are considered to be Near Colorless. Near Colorless diamonds are still considered to be above average, but are usually less expensive than Colorless diamonds. These types of diamonds are a great buy and an alternative to the pricier Colorless Diamonds.

Diamonds that are assigned a K-M, N-R, and S-Z are considered to be faint yellow, very light yellow, and light yellow. These types of diamonds are considered to be of lower quality and the imperfections are obvious to an untrained eye.

There is one final class of Diamonds. This is the Fancy Colored Diamonds. This is reserved for diamonds that are very brightly colored. Fancy diamonds, like the red diamond, are extremely rare and can be very pricey. This is not always the case though because it is possible to get some great deals on green, blue, or bright yellow diamonds.

The Aurora Diamond Collection is a well known collection of diamonds that is considered to be the most comprehensive collection of diamonds in the world. It contains the extremely rare red diamond. The Aurora Diamond Collection, currently on display in London, is probably the best way to get a feel for the different colors that diamonds can be. While most of us will not be able to make it London, there are many pictures available on the internet that can give you an idea of the different colors found in diamonds.