Diamond Classification - Consumer and Technical

Imagine a scenario in which you’re running from one person to another for information on diamond stones before going to buy jewellery. In most of the cases, people would tell you to look for 4Cs of diamonds: cut, clarity, colour, and carat. While they’re right in their judgement to advise you to examine these four diamond characteristics, they often fail to mention one critical aspect of diamond jewellery shopping: the classification of diamonds. 

As a consumer, your outlook on choosing a diamond rock accessory as compared to a gemologist varies to a high degree. And although the four diamond characteristics do justice to help you pick out the most brilliant diamond, they usually are gemologists way of sorting diamond on a scale and grading them, rather than for buying purpose. 

In this guide, we take your knowledge to another high as we describe what is meant by classification of diamonds, and how the consumer diamond classification is different from the technical one.

From the outside, all the diamonds may appear similar to you, but in their chemical and physical properties, they vary to great lengths. Gemologists have classified diamonds based on two aspects and use this classification to evaluate the stones for their atomic structure and jewellery making usage. Upon assessing the atomic makeup of a diamond, gemologists then analyze its growth, colour, and more importantly, whether it is real, synthetic or treated. This guide explores the gemologists point of view of analyzing a diamond stone based on its classification as well as the consumers’ viewpoint to examine diamond jewellery before finalizing on their product of choice.

However, before diving deep into the topic, let’s discuss how diamonds are classified. 

It all starts with the formation of diamonds in their natural habitat. As a pure form of carbon, these sparkling stones rarely contain any high traces of any other mineral in them. However, in the Earth’s crust, diamond rocks are known to trap small traces of Nitrogen and boron, giving them an impression of flaw. These defects are also termed as lattice defects, and their absence, as well as presence, have an effect on the stone, which are divided into consumer classification and technical classification.

As a consumer, there is no need to drown yourself in technical aspects of diamond jewellery. No matter what you’re looking to buy, a ring studded with diamond stones or a simple pair of sparkling earrings, the technical aspects of a diamond, such as its diameter or chemical composition mustn’t hamper your purchase decision. Instead, you must focus on the below factors to come to a diamond jewellery purchase decision as a consumer.

Natural diamond rocks: By the name, you could deduce that these stones are formed in their natural habitat (Earth’s crust) and are brought to the inner Earth’s surface by volcanic eruptions. Most of the natural diamonds are colourless with only a small hint of yellow tint that is due to trapped gases in the stones. You can ask your gemologist or the retailer to provide you with diamond certificates of your jewellery purchase to cross-check their colour, shape, and origin.

Synthetic diamonds: Again, as the name suggests, synthetic diamonds are manufactured in the labs by scientists, but contain the same chemical and physical properties as natural diamonds. Human-made diamond stones are real diamonds and have all the characteristics to be added in a pair of bangles or nose pins, or any other jewellery item.

Artificially-treated natural diamonds: These diamond rocks are formed and mined from their natural habitat but undergo lab-based treatment and processes to make them appear suitable for jewellery making. One of the methods is hiding the inclusions of the diamond stone to make it look brilliant and nearly colourless. Another lab-based treatment is the colour enhancement, which improves the overall look of the stone to appear sparkly and brilliant. 

Note: Not all natural diamonds are treated. Treatments are done only on those diamonds that cannot be sold in their natural form. Treated diamonds are sold for lower prices than their natural counterparts.

Naturally coloured diamonds: Most of the naturally found diamonds are colourless or nearly colourless. But a fraction of them is also coloured. Although quite rare, naturally coloured diamond rocks are available in different shades, such as blue, green, black, and purple. Among them, the common colour of diamonds to be found naturally are pink and canary yellow. 

Note: Due to their rarity, naturally coloured diamonds are quite expensive as compared to other diamonds. But consult a gemologist or the retailer for better understanding of the diamond and its price as per its different characteristics.

As a buyer, it is also vital for you to know about the technical classification of diamonds, although they might not influence your purchase to a high degree. Then, why must you know about the technical classification at all? Because the presence of even a slight amount of impurities in the diamond drastically impacts its market value.

We have mentioned above how Nitrogen, Boron, or other gases get trapped in the carbon and form lattice defects in natural diamonds, causing chemical as well as physical impurities in the stone. While these irregularities might not be visible to the naked eye, they do affect the price and grading of diamonds. Based on these defects, diamonds are technically classified into four sections:

This type of diamond rock contains a large cluster of Nitrogen in the crystal lattice, giving it a yellowish appearance. Especially when Nitrogen atoms occur in a group of three or more, they absorb the wavelengths of visible light on the blue end spectrum, resulting in yellow light reflection.

Furthermore, Type Ia diamonds are categorized into IaA and IaB, where the former refers to diamond stones containing nitrogen aggregates in pair. In contrast, the latter refers to diamonds containing nitrogen aggregates of four atoms. Neither of these two diamond types can absorb any visible light. 

Note: Type I diamonds, as a whole, are the most common. They are also known for their characteristic fluorescence and ability to absorb infrared and ultraviolet light.

As opposed to Type I diamonds, Type II diamonds contain negligible to no impurities and are one of the most valuable diamond stones to be preferred for jewellery making. In fact, among all the types of diamonds, Type II are the rarest and constitute just 1% of all the mined diamonds. Not only do they have a stunning and brilliant colourless appearance, but they also occur in different shades of pink, grey, yellow, brown, light blue or light green, if any minute inclusion absorbs a light. Additionally, these precious stones are formed under immense pressure that they tend to have an irregular shape, which is made ideal for jewellery usage after cutting and polishing.

Compared to the Type Ia diamond stones, Type Ib rocks are not common in nature and constitute only 01% of total naturally mined diamonds. 

In Type Ib diamond stones, instead of a cluster of nitrogen atoms, only a single nitrogen atom is dispersed throughout the crystal lattice. And since they are scattered, visible light on the blue end of the spectrum is absorbed, resulting in an intense colour – usually yellow, orange or brown.

Similar to IIa diamond type, this diamonds classified under IIb lack any traces of Nitrogen as an impurity. However, they contain boron within their structure, giving them certain characteristics that are unknown to diamonds usually.

For starters, the presence of boron makes diamonds electrically conductive, and also gives them a bluish or bluish-grey tint as boron absorbs light on the red end of the spectrum. Moreover, representing only 0.1% of diamonds, Type IIb diamond stones are scarce and highly valuable as well.