The 4C’s of diamond grading revisited

4C's diamond

The 4C’s and the Appearance Based Choice of Diamond (ABCD)

The 4C’s is well designed but rather professionally orientated classification system. When it comes to diamond choice, whether for engagement rings or as gift for any occasion, one is often engulfed by an ocean of controversial information which seems to grow in complicity as one learns more. First comes the 4Cs system and its implications on the price. Then as soon as one figures out what is all about, there comes the certificate origin, proportions, fluorescence and many more, each one claiming different degree of importance.

At the average cost of two to three monthly salaries it is not difficult to see why the potential diamond buyer is determined to make the right decision. While the 4C’s is well designed classification system, my honest opinion is that the marketing efforts of the diamond merchants are often misleading, pushing the buyer to an unfavourable choice.

Why would the merchant do this? The logical reason is the bigger profit related to more expensive merchandise on all trade levels, thus the interest to promote certain qualities in favour of others. I have about 30 years of experience in designing and selling diamond jewellery, and dealing with the 4C’s. My opinion is based on that experience rather than on statistics or scientific research. I am trying to simplify the riddle of choosing the right diamond and separate the information that really matters from the one that doesn’t.

Investment diamonds

From this point I want to separate the diamonds bought for investment purpose, and possible intention to sell over time for profit. Although you will be often assured that the diamond you are buying is of investment quality this is most of the time half truth. Diamonds which can generate considerable appreciation are classified as extremely rare and are also extremely expensive. They should be of top colour and clarity, and most important, over 2 preferably 3 carat in size.  I have another article dedicated to investment diamonds for those who want to know more. For the purpose of this topic, it will be enough to say that if your diamond costs less than $50 000 it is unlikely to generate reasonable interest.

With this in mind the only other purpose of a gem quality diamond is its beauty. Since the beauty of the diamond is in its appearance, choice focused on qualities that visibly contribute to the appearance should constitute favourable choice. The key word here is visible. The 4C’s segments, forming the diamond quality are making difference in its appearance, but while some are really evident others are completely undetectable for unaided eye. Addressing those segments in order of importance will certainly result in locating the best value for money choice. The 4C’s segments in order of importance appearance wise are: Cut, Carat, Colour and Clarity.


Cut is a 4C’s attribute hardly mentioned when diamonds are quoted. It is however of major importance for the appearance of the diamond. The amount of light reflected back from the facets of the gem creates the look diamonds are famous for. Ideal cut is not a necessity but a bonus if it does not add to the price. Excellent and very good graded diamonds are safe choice, but anything under that must be approached with caution.


.Size does matter when it comes to diamond appearance. Many women will state that small diamond of good quality is OK, but they seldom mean it. The lack of sufficient information and inability to compare different options are most likely the source of such opinion. It is very difficult (financially) to go for a diamond which is too big. Diamonds are very expensive even in small sizes and an effort to save for future expenses with higher priority is fully justified. My advice is not to spend more but to consider the biggest size within certain budget. The appearance of a large diamond cannot be emulated by a cluster of small ones. Even a difference of 0.2mm in diameter is surprisingly noticeable.


Going down on colour is possible. I agree that the exceptionally white D, E and F grades are stunning. However I,J and even K colour, looks  white, if presented on its own and not next to a whiter stone to compare. Untrained eye will never notice the difference. Choosing colour J instead of F for example will award you with considerably larger stone with far greater appearance impact.


We try to avoid high clarity when applying  Appearance Based Diamond Choice. Clarity is the 4C’s segment one could safely save big and push far the size or/and colour of one’s diamond. Inclusions in SI 1 graded stones are usually invisible for the naked eye. They definitely do not affect the overall appearance of the diamond. The clarity grading system is based on size and number of inclusions and not on their colour and position within the stone. Diamond graded SI2 with small scattered white inclusions close to the girdle will appear much cleaner than one graded VS2 because of a single small black dot in the center of the table, reflected many times form the facets. The price however will be based not on the appearance but on the grading and the difference will be huge.

You can use my expertise to help you with your diamond choice. I have been doing this for years and have plenty of customers ready to provide reference if needed.