Type IIa Diamonds

If you've recently purchased a lab-grown diamond, you may have noticed the term "Type IIa" on its grading report. This classification indicates that the diamond is among the most chemically pure, containing little to no nitrogen or boron impurities. Type IIa diamonds are renowned for their exceptional clarity and brilliance, attributes that make them highly sought after in the jewelry market. While only about 1–2% of natural diamonds fall into this category, a significant proportion of lab-grown diamonds are Type IIa due to the controlled conditions under which they are created. Understanding this classification can enhance your appreciation of your diamond's quality and value.

What are Diamond Types?

Diamonds are scientifically classified into two main types based on the presence of impurities: Type I and Type II. Type I diamonds, the most common, contain nitrogen impurities and are further subdivided into Type Ia and Type Ib. Type Ia diamonds have nitrogen atoms in clusters, while Type Ib diamonds have isolated nitrogen atoms. Type II diamonds lack measurable nitrogen impurities and are divided into Type IIa and Type IIb. Type IIa diamonds are the most chemically pure, often colorless, and highly sought after. Type IIb diamonds contain boron impurities, giving them a blue or gray hue and the unique ability to conduct electricity.

Market Perception and Valuation of Type IIa Diamonds

One evaluating diamonds one must thoroughly evaluate its characteristics; whether they are type Ia diamonds or a type IIa diamonds may be irrelevant to its true value.  Although type IIa diamonds are more rare that does not necessarily mean they will always be more valuable than a type Ia or even Ib or IIb.  President of Graff USA, Henri Barguirdjian explains, "we try to summarize two or three elements – color, clarity, type, fluorescence.  Not just one quality on a piece of paper."  Barguirdjian explained that auction houses are responsible for the current market atmosphere regarding type IIa diamonds and Barguirdjian explained that auction houses are responsible for the current market atmosphere regarding type IIa diamonds.  Furthermore, he notes the popularity of type as price determines of diamonds that has only occurred within the past 5 to 7 years.  This is the case because the Gemological Institute of America only started designating the different diamond types within the past 10 years.  These labels, in turn, provided consumers with yet another mechanism to differentiate and evaluate diamond values.

Understanding Type IIa Diamonds

Type IIa diamonds are renowned for their exceptional purity, containing no measurable nitrogen or boron impurities. This chemical purity grants them the highest thermal conductivity among diamonds, enhancing their brilliance and making them highly sought after. Typically, Type IIa diamonds are colorless or near-colorless, but they can also exhibit subtle hues of gray, light brown, yellow, or pink due to structural anomalies during formation.

In nature, Type IIa diamonds are exceedingly rare, comprising only about 1–2% of all mined diamonds. However, the majority of lab-grown diamonds fall into the Type IIa category. This is because the controlled conditions under which they are created minimize the presence of impurities. As a result, when a diamond is identified as Type IIa during testing, it often indicates a lab-grown diamond origin, given the scarcity of such purity in natural diamonds.

Type IIa Diamonds at the Golconda Mine 

Since diamonds have been separated into four distinct subtypes: Ia, IIa, Ib, and IIb there has been a misuse and overuse of the term type IIa especially when the Indian mine Golconda is mentioned.  It is without a doubt that the Golconda mine has produced some of the finest diamond material in the world however not all diamonds retrieved from the Golconda mine are type IIa.  Many people assume that the all the diamonds from this prestigious mine are of exceptional material, shine, and brilliance.  Unfortunately, that is not the case.  It is important to note that the term Golconda and type IIa are not interchangeable. Chairman of Sotherby's jewelry department for the Middle East and Europe, David Bennett goes on to say "before GIA and certificates became de rigueur, you talk about 'first water' or 'limpidity' and every new what you are talking about.  Many diamond producing regions produce type IIa stones, including Brazil, South Africa, and Central Africa.

Type IIa Diamonds and GIA Certificates

If you are going to have a white diamond, type IIa is the cherry on the cake.  It's something you can say about it, another detailed, something positive.  There is no reliable diagnostic tests that can show categorically that a diamond is of a certain geographic origin.  What we do know is that the prime origin of diamonds from antiquity was Golconda.  Rappaport Magazine, recently spoke with Tom Moses of GIA about the overuse of the term type IIa, he says "we have always been careful to stay that there is no scientific means to determine the geographical origin of diamonds, so I am not overly concerned what may be inferred from a GIA letter." Nevertheless, GIA, as well as other diamond grading laboratories, indicate the type for a specific stone.  This lends credibility to its importance.  For example, in May 2013 Christie's held an auction in Hong Kong for a pearl and diamond pendant.  They were accompanied by two laboratory certificates; one certified by the Gemological Institute of America and the other a prestigious Swiss lab Gubelin.

Type IIa Diamonds and India

The GIA letter reads as follows. "Type 2a diamonds were first identified as originating from India.  Particularly from the Golconda region, but have since been recovered and all major diamond-producing regions of the world." The pendants other certificates by Gubelin that the "diamond of this type exhibiting an antique cutting style as well as a fine quality are very rare and will most certainly you vote references to the historic term of 'Golconda." Some suggest these catalog comments are an invitation to distort the line between type IIa and the historic Golconda designation.

Famous Type IIa Diamonds 

Earth-mined Type IIa diamonds are exceptionally rare and highly prized for their unparalleled purity, substantial carat weights, and historical significance. These natural diamonds , devoid of measurable nitrogen or boron impurities, are among the most chemically pure gemstones known.

The Elizabeth Taylor Diamond: Originally known as the Krupp Diamond, this 33.19-carat Asscher-cut gem was gifted to Elizabeth Taylor by Richard Burton in 1968. Renowned for its D color and VS1 clarity, it was later classified as a Type IIa diamond by the Gemological Institute of America. In 2011, it fetched $8.8 million at a Christie's auction, setting a record price per carat for a colorless diamond at that time. 

The Cullinan Diamond: Discovered in South Africa in 1905, the Cullinan Diamond remains the largest gem-quality rough diamond ever found, weighing an astounding 3,106.75 carats. This Type IIa diamond was meticulously cut into nine major stones and 96 smaller brilliants. The largest cut, the 530.2-carat Cullinan I, also known as the Great Star of Africa, is set in the British Sovereign's Sceptre with Cross. The combined value of the Cullinan diamonds is estimated to be in the billions. 

The Pink Legacy Diamond: This extraordinary 18.96-carat Fancy Vivid Pink Type IIa diamond captivated collectors with its intense hue and rarity. In 2018, it was sold at a Christie's auction in Geneva for $50.4 million, achieving a record-breaking price per carat for a pink diamond. The gem was subsequently renamed "The Winston Pink Legacy" by its new owner, Harry Winston.

These illustrious examples underscore the exceptional value and allure of natural Type IIa diamonds, celebrated for their unmatched purity, size, and historical prominence.

http://www.rwwise.com/tgd2.html http://www.nytimes.com/2011/03/18/fashion/18iht-acaj-diamonds-18.html?pagewanted=all&_r=0 http://www.nationaljeweler.com/diamonds/supply/95-carat-Type-IIa-d-2541.shtml Four Types of Diamond Classes