Diamond is a solid form of carbon with a diamond cubic crystal structure. At room temperature and pressure it is metastable and graphite is the stable form, but diamond almost never converts to graphite. Wikipedia
4C represents Color, Clarity, Cutting and Carat. The 4Cs are the shared common attributes used by different grading institutes, to determine the quality and value of each diamond. Therefore, it is crucial to know the 4Cs before buying a diamond.
Carat is the weighting unit of a diamond, as below:
1 carat = 0.2 grams = 0.007 oz.
Bigger diamonds are rarer, as such, the value per carat will also be higher. For example, the value of a 1 carat diamond would be much higher than the total of two 0.5 carat diamonds.
The weight of a diamond affects its size, although the same weight may lead to different sizes, the following table shows the approximate size to weight ratio:
Diamond with no magnification
Diamond at 10x magnification
Clarity refers to the inclusion and blemishes of a diamond; the level of clarity is determined by the number, size, place, whether it is obvious and the general effect of those inclusions and blemishes to the appearance of a diamond. Since diamonds are formed naturally, the formation process would usually include some other substances which lead to so called crystals, feathers inside a diamond. Better clarity gives a higher value of a diamond.
The GIA Clarity Scale contains 11 grades. In determining a clarity grade, the GIA system considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.
Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) – No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) – Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader under 10x magnification
Included (I1, I2, and I3) – Inclusions are obvious under 10× magnification and may affect transparency and brilliance
Since the diamond with “Included” grading includes quite obvious inclusion, we do not recommend and also do not offer diamonds with Grade I1 , I2 & I3 , except customers request us to provide.
It refers to the level of colorless of a diamond. The rating is from D to Z. For D color, the best color level, representing colorless and continues with increasing presence of color to the letter Z, or light yellow or brown, as shown below:
|COLORLESS||NEAR COLORLESS||FAINT YELLOW||VERY LIGHT YELLOW||LIGHT YELLOW|
Many of these color distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.
Color and clarity are born naturally with a diamond; however, on the other hand, Cutting is determined by the craftsmanship the diamond receives, which is an important factor to lead the diamond to sparkling perfection. The cutting factor involves complex determination, as a value factor, though, it refers to a diamond’s proportions, symmetry and polish.
The proportions of a diamond refer to the relationships between table size, crown angle and pavilion depth. A wide range of proportion combinations are possible, and these ultimately affect the stone’s interaction with light.
GIA diamond graded cutting into 5 categories, from Excellent to Poor.
The Hope Diamond and the Graff Pink – extraordinary Type IIa Diamonds
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.
Type 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…
Types of Diamonds – Consumer Wise
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.
2. 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.
3. Man Made Diamonds
Man-made diamonds also known as lab grown diamonds are somewhat of a 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 man-made diamonds were %30 beneath equivalent regular diamonds today they are %50 cheaper and some say that in a few years they will become even 70% cheaper and more.
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…
Types of Diamonds – Technical Explanation
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:
Type Ia Diamonds
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.
Type Ib Diamonds
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.
Type IIb Diamonds
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.