Diamonds are specifically classified into four types on the basis of impurities contained by them in themselves or the level of infrared absorption spectrum.
The types of diamonds are classified in two categories Type 1 and Type 2. These two categories are sub classified in further two categories each.
Type 1a, Type 1b, Type 2a and Type 2b. 1a and 1b are the natural forms of diamonds in which they are found.
Type 1
Nitrogen is the main impurity for Type 1a diamonds and can absorb infrared and ultraviolet region by 320 nm. They are about 98% of the total volume of the diamonds. These diamonds are pale or almost colorless due to absorption characteristics of nitrogen in it as a main impurity. They can absorb blue light quite easily. The Type la diamonds are found in huge amount at Cape Town a province of South Africa.
In Type 1b of diamonds nitrogen is found in very low quantity (0.05%). Due to more diffused atoms in these form of diamonds they can absorb green and blue lights and give dark brown and yellow color. This type of diamonds contributes a very less amount of total quantity (0.01%).
Type 2
In this class of diamonds impurities are immeasurable. These diamonds are about 2% of the total diamonds found and also of gem diamonds. Theses diamonds need very high temperature and depth to be formed. These diamonds show orange, pink, brown, red purple and yellow colors due to its impurities.
Type 2b diamonds are only 0.1% of the total quantity of diamonds. Boron is the main impurity in this type of diamonds and these diamonds contain the least amount of impurities. Boron makes theses diamonds to absorb red, yellow and orange colors.
