Type of Diamondsadmin
Diamond typing is important to researchers and laboratories, but largely irrelevant to consumers. Determinations of diamond type are made on the basis of differences at the atomic level. Diamond is composed almost entirely of carbon atoms aligned in a very specific crystal lattice, but other atoms such as nitrogen and boron are commonly trapped among the carbon atoms during formation. While other impurities can also be incorporated, the diamond type classification system divides diamond into categories based solely on the presence or absence of certain nitrogen and boron impurities and the ways in which they are structured. Which one is present and how it is arranged in the carbon lattice determines the diamond type. The primary benefit to gemologists in understanding a diamond’s type is in being able to distinguish natural from synthetic and treated diamonds.
The most common is type I, consisting of type Ia and type Ib. Type I diamonds contain Nitrogen impurities, either in aggregates (Type Ia) or in isolated atoms (Type Ib). While different types are associated with different fancy colors, the vast majority of consumers will be considering diamonds in the normal range “D-Z”, and 95% of those diamonds will be type Ia. Some of the rare type Ib diamonds will have a vivid yellow color, sometimes referred to as ‘canary’. Nitrogen centers are also associated with fluorescence.
Type Ia are further broken down on the basis of how the nitrogen aggregates are configured within the carbon lattice. When the nitrogen atoms are separated in pairs, they are designated type IaA. When they surround a vacancy (a missing carbon atom), they are type IaB.
Type II diamonds are those with a non-detectable amounts of nitrogen. Type IIa diamonds have negligible impurities of any kind, while Type IIb are those with atoms of the element Boron trapped in the carbon lattice. Type IIb diamonds are associated with fancy blue diamonds.