
Examing transparency under ultraviolet radiation, diamond categorized into two types. Further sub-categorized based on carbon and impurity atoms in the structure. Called as Type Ia diamond, Type Ib diamond, Type IIa diamond & Type IIb diamonds.
Pronounced as “Type-one-a”, “Type-one-b”, “Type-two-a” and “Type-two-b” diamonds. Don’t confuse it with alphabet “i”. Diamond type categorized with the roman numbers I & II.
Understanding Diamond Type Ia, Type Ib, Type IIa & Type IIb
Let us understand science about how diamonds categorized into different types.
Type I diamonds are the most common class of diamonds. It contains nitrogen as the main impurities into its atomic structure. Whereas Type II diamonds do not contain nitrogen. It reacts differently when exposed to ultraviolet radiation. Only high-end equipment can measure on the atomic level within the crystal lattice of atoms.

Ia Diamond
About 95% of diamonds are type Ia. Plentiful of nitrogen and its atom are in pairs or clusters. Usually nearly colorless to yellow in color. Laboratory-grown diamonds cannot be of type Ia class. If you hold a diamond which is verified as Type Ia. You are having a natural diamond.
Ib Diamond
Contain less nitrogen compare to Type Ia diamonds. Type Ib diamonds have scattered and isolated nitrogen with its atomic structure. Ib diamonds occur rarely in nature and have a more saturated yellow color. Laboratories can grow such diamond type with controlled temperature, pressure & vacuum with machines.
IIa Diamond
Diamond without any impurities and almost absence of nitrogen. Type IIa diamonds occurs very rarely in nature and are usually colorless, brown or gray. Purely made of carbon atoms and such diamonds are an excellent conductor of heat. Majority of world famous diamonds are Type IIa. Also, Laboratory-grown diamonds are mainly Type IIa diamonds.
IIb Diamond
These diamonds contain boron which leads to blue color in diamonds. Less than 0.1% of all natural diamonds are Type IIb diamonds. World’s famous 45.52 ct “Hope Diamonds” is the best example of Type IIb diamond. IIb diamonds are an excellent conductor of electricity. Also, Blue color diamonds are extremely rare and expensive.

I suggest submitting a diamond to a reputable laboratory for accurate results. Gemological Institute of America is our recommendation.
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Content and Image Reference – GIA
5 thoughts on “What is diamond Type Ia, Ib, IIa & IIb?”
Thank you harsh! for sharing wonderful insights about diamond types.
Thanks for stopping by and adding your valuable comment. Have a good day.
Thanks, Harsh . Great Explanation , waiting for your next blog. Keep it on.
Hi Jyoti, Thanks a lot for stopping by and adding your valuable feedback. Comments like this push me to write more informative content about diamonds and help people. Good day!!
Hi Jyoti, Thanks a lot for stopping by and adding your valuable feedback. Comments like this push me to write more informative content about diamonds and help people. Good day!!