Diamonds Classification and their impurities

Pure diamonds are composed entirely of carbon.  However, diamond crystals contain minute quantities of trace elements that can take the place of some carbon atoms and the most common form is nitrogen.

A trace element is a an element that occur in minute quantities.  Because of their impurities, diamonds are classified into two types.  Type I and Type II.

Type I - Nitrogen occur as the major impurity up to 0.2%.
Type II - Do not contain nitrogen as a significant impurity. Type II diamonds also contain nitrogen but does not affect the physical properties.

Diamonds with large concentration of nitrogen impurities start with a single isolated atom. Due to the geological condition of heat and pressure over time, the nitrogen migrate thru the structure to form pairs and then aggregates of there or four nitrogen atoms which are Ia.

Type Ib transform into Type Ia.


The majority of natural diamonds are Type Ia.

Type Ia diamonds are diamonds that contain nitrogen atoms as pairs or small groups called aggregates.

Type IaA- diamonds contain aggregates of 2 nitrogen atoms

Type IaB -  or groups of 3 or 4 nitrogens called aggregates with vacancies.  Groups of 3 surrounding a vacancy are called N3 color centers.