Types of Diamonds
When we talk about " diamond types" we are not talking about folks who really like diamonds. Actually, it's pretty scientific -- a system of classifying diamonds according to trace elements in the crystal. The trace elements are trace impurities.
If you have never heard of Type I and Type II diamonds its because the concept is relatively new. And that's because the impurities can only be detected with an infrared spectrometer.
The impurities that determine diamond type dwell deep in the lattice of a diamond crystal. These trace elements are figuratively invisible, millions of times smaller than the tiniest inclusion. But we do see their effect on a diamond's color. The impurities affect color through a mechanism of absorption. See our page on optical properties of diamond crystals. (coming)
Some of the diamond type techno-speak is difficult for us lay-persons to understand, even to comprehend. So why is it important? Because "diamond type" is about color. There are also rarity factors involved with diamond types.
Type I Diamonds
Type I diamonds are most common. Nitrogen is the impurity. Type I diamonds are further categorized as Type Ia & Type Ib.
Type Ia - estimated that 98% of all natural diamonds are Type Ia with nitrogen concentrations up to 0.3%. Type Ia diamonds have another sub-classification.
- Type IaA - The nitrogen atoms are in pars and don't effect the diamond's color
- Type IaB - Nitrogen atoms form in large even-numbered clusters and result in yellow / brown.
Type Ib diamonds are much more rare. Only about 0.1% of natural diamonds are Type Ib. The nitrogen in these crystals is only 0.05% and is widely distributed. As a result, the crystal absorbs the green spectrum. That means the diamonds tend toward more vivid colors of yellow and brown.
Type II Diamonds
Formed under extremely high pressure and temperature, these diamonds have no impurities. Only 1-2% of natural diamonds are Type II. Besides being colorless, Type II's tend to form large and irregular crystals. One example of a @ Type II diamond crystal
Type IIa - these are probably the best of the best, 2% of all natural gem diamonds. Australian diamonds tend toward Type IIa. Some very famous diamond are Type IIa. Example are the @ Cullinan and the Koh-i-noor
Type IIb - Even rarer than Type IIa at 0.1% of all natural diamonds, Type IIb diamonds have insignificant nitrogen impurities. What sets them apart is boron. Boron impurities tend to produce diamonds with a blue or gray tint.
