The Different Types of Diamonds

Not all diamonds are created equal. Yet when most people think about diamond differences, they're more likely to consider the 4 c's - cut, clarity, color and carats - before classification. Is your diamond round or square? Is it clean or included? What is the diamond’s color? But these are diamond grading attributes and not diamond types.

The Types of Diamonds classification system separates stones based on their physical and chemical properties. By evaluating the atomic makeup of a diamond, gemologists can analyze its growth, color and more importantly, whether it is real, synthetic or treated.

BUT, if you are not conducting a theoretical survey or studying gemology – this is probably not what you had in mind, and therefore...

A hard sentence to but I meant it. In this article I will cover everything to do with diamond types. But there is the GIA’s way and there is the consumer’s way to classify diamonds. I will start with the consumer’s definition:

In the eyes of the consumer, there are four main diamond types:

1. Natural Diamonds

Regular white colorless diamonds. Not much to expand on them. Basically, these are probably what everybody imagine when you speak with them about diamonds.

Before jumping to the next section, one of the below diamonds is a natural diamond and the other is a lab-grown diamond... Can you tell which is which?

2. Lab Grown Diamonds

Lab grown diamonds also known as man-made diamonds are somewhat of a growinng trend that is developing more and more last few years. The reason is that it is a technological product just like any other “gadget” (no disrespect intended). As such, as technology evolved, these diamonds become cheaper and cheaper to manufacture. While once prices of lab grown diamonds were 30% beneath equivalent regular diamonds, today they are 50%-60% cheaper and some say that in just a few years they will become even 70% cheaper and more.

For example, both of the above diamonds are 1 carat, G color with SI1 clarity and excellent cuts. One costs about $6,000 and the other $2,000. To learn more about diamond prices, check out our live diamond price calculator.

Below is a graph showing the interest in this type of diamonds over the past five years:

3. Treated Diamonds

Diamonds that were mined like the regular diamonds mentioned above but that their attributes were artificially enhanced / manipulated to get a better looking diamond. Common treatments include inclusion filling where using special material they “hide” inclusions and color enhancement. Please note that these treatments are usually done to diamonds that cannot be sold otherwise and therefore these diamond prices are dramatically lower than the equivalent natural non-treated diamond.

4. Natural Fancy Color Diamonds

Last but definitely not least… These are the most beautiful type of diamonds (but I’m not objective :) ). Colored diamonds are extremely rare… approximately 1 to 10,000 compared to regular diamonds. The spike in awareness (and with it demand) came last decade as more and more celebs were seen wearing them – whether as fashion statements on the red carpet or received them as engagement rings… Most famous are the pink diamonds and canary yellow diamonds but these gorgeous diamonds come in all colors of the rainbow – Blue, purple, violet, red, green, yellow, gray, white, black… as well as combinations of these colors.

Basically there are hundreds of dazzling colors – you can drill deeper in our complete guide to diamond colors.

Being so rare and expensive, these diamonds are also divided into subsets - Natural colored diamonds, Treated colored diamonds and lab grown colored diamonds.

The most commonly known example (or not known) is the one of black diamonds. Black diamonds are actually very rare.

Natural black diamonds cost about $3,000 per carat but black diamond rings (as the one here on the right) cost about $1,000… The reason is that these rings often show treated diamonds. Diamonds that had so many inclusions that the only solution was to hide them by “painting” them black…

The truth is, you can read a diamond's history merely by knowing its type. This is because when diamonds are initially forming, certain elemental atoms - typically nitrogen - may substitute carbon atoms inside the crystal lattice. Later, those atoms will move within the structure, often clustering together. These chemical impurities and structural anomalies are not visible with the naked eye, but they affect the diamonds' color and appearance.

What's most unusual about the classification system is that a single stone can actually be assigned more than one Diamond Type. Once experts, such as those at the Gemological Institute of America, decide what a stone's true classification is, they will mark this type on the certificate.

So how is this information relevant to you as a diamond buyer? Surprisingly, those small traces of nitrogen can translate to a big price difference. Diamonds are a considerable investment, and as their type is directly related to their value, it's crucial to be able to distinguish the classifications. Here's what you need to know about the different diamond types:

The first thing you'll notice about type Ia diamonds is that the emit a yellowish tone. Why? Because they contain nitrogen in aggregates - or large clusters - throughout the crystal lattice.

When the nitrogen atoms occur in groups of three, these aggregates absorb wavelengths of visible light on the blue end of the spectrum. As a result, the light that is reflected appears to be yellow.

It's worth noting that Ia diamonds can be broken into subcategories: IaA and IaB. The former refers to diamonds with nitrogen aggregates in pairs, while the latter contains aggregates of four nitrogen atoms. Neither type can absorb any visible light. Type I diamonds as a whole are the most common, and are known for their characteristic fluorescence as well as absorption of infrared and ultraviolet light.

Type IIa Diamonds

Type II diamonds have differing fluorescence and no visible absorption, no nitrogen impurities that may cause a yellow or brown tint. Additionally, type II diamonds form under remarkably high pressure for longer time periods, and tend to have an irregular shape.

Of all the diamond types, type IIa diamonds are the most rare valuable and therefore, the most sought-after by collectors and investors. In fact, this type represents just 1 percent of all diamonds, so they are highly valuable and obviously a superior choice for investment. The reason why these stones are so exceptional is that they contain very little nitrogen or none at all within the crystal lattice, so they do not easily absorb short-wave light.

The result is that light is easily able to pass through and bounce back at the beholder's eye, producing a stunning appearance. Because they are almost pure carbon, white diamonds are remarkably colorless, unless they contain an inclusion that absorbs certain light. Fancy colored diamonds of this type can be pink, gray, yellow, brown, light blue or light green.

Sometimes these stones are referred to as "Golconda Diamonds" after the Indian mines that produced some of the best gems in the 16th and 17th centuries. For customers who are seeking the "perfect" diamond, type IIa, with D color, no fluorescence and IF or VVS1 clarity is ideal.

Many of the most famous diamonds throughout history have been this type. The world's largest cut diamond - the Cullinan - is one example. The Koh-i-Noor and its sister diamond, the legendary 45.52-carat Hope Diamond, The Graff Pink (previously world's most expensive diamond) and the De Beer Millennium Star are also type IIa. Additionally, the 33.19-carat Asscher-cut "Elizabeth Taylor Diamond," which was bought by Richard Burton in 1968 for his wife's ring, is this type.

This type is not as common as type Ia - in fact, it represents less than .1 percent of natural diamonds. In these stones, single nitrogen atoms instead of clusters are dispersed throughout the crystal lattice. Because they are scattered, a lot of visible light on the blue end of the spectrum is absorbed, resulting in an intense color - typically yellow, orange or brown, according to the GIA. True canary diamonds are a perfect example of this. In some cases, yellowish green diamonds can contain this atomic formation.

Like type IIa, this type lacks nitrogen atoms within the crystal structure. However, these stones contain a distinct difference from the other types: boron.

The presence of this element not only makes these diamonds electrically conductive, but also gives most of them a bluish or bluish gray tint. This is because boron absorbs light on the red end of the color spectrum.

Type IIb is also extremely rare, representing only 0.1 percent of diamonds, and are thus highly valuable. For some, the blue tone can be a visual advantage.