What a Type IIa diamond is

Diamond type is assessed separately from the 4Cs, and diamonds are usually divided into four types:

Type Ia and Type Ib

Contain more nitrogen, tend to look yellow and are mostly used in industry.

Type IIa

Contain almost no nitrogen.

Type IIb

Contain a small amount of boron, and are favored by the semiconductor industry.

All colorless CVD lab-grown diamonds are Type IIa.

Favored by collectors

A colorless Type IIa diamond is often compared to a pool of clear spring water, light and transparent. The jewelry trade also calls Type IIa diamonds “the purest of the pure” or “beyond D color,” a shade more beautiful than an ordinary top-grade D Flawless diamond, and they are highly prized by collectors. Famous diamonds such as the 33.19-carat Elizabeth Taylor Diamond, the 530-carat Cullinan and the 317-carat Cullinan II are all Type IIa.