摘要
It is well known that nitrogen is a major impurity in diamond because it can substitute the carbon in the diamond lattice. Hence diamonds may be classified as TypeⅠor Ⅱ based on the nitrogen content. The diamonds with higher nitrogen content are classified into Type Ⅰ. Diamonds in which nitrogen is mainly present in aggregated form are put in Type Ia, whercas those in which nitrogen is mainly present in dispersed and isolated form into Type Ib. Synthetic diamonds often belong to Type Ib. However,
