What is the carat of the diamond?

How did we arrive at this measure and how do we weigh a diamond?

Carob seeds were used by early gemstone traders as counterweights in their scales. First adopted by the United States in 1913, this unit is now widespread worldwide. No matter where you are on earth, a carat will always weigh the same. To weigh a diamond, you need a scale that must be installed away from drafts, vibrations, and heat sources. These conditions are necessary to avoid distorting the result. The stone must be clean. It is also necessary to check the accuracy of the scale: zero it, weigh it empty, then weigh it with the stone. For the result, you should always put 2 digits after the decimal point. Even if your diamond weighs 3 carats, it should be written as 3.00 carats. (Fun fact: it is not uncommon to see "ct" written instead of "carat").

Is the carat the most important factor when buying a diamond?

There is a common misconception about the carat... Indeed, many people imagine that the carat is the most important factor when buying a diamond! This idea is false. The brilliance, the sparkle, shining with a thousand fires, that's what defines the appearance of the diamond! These qualities are determined by the size of the diamond, not its weight. A diamond cut perfectly with excellent proportions will be the most brilliant, more carats on this diamond will give much larger facets. Which to your eyes will make the diamond more sparkling.
Your priority when buying a diamond is to get the best possible cut and then adjust the carat weight according to what you like the most.

But why is the cup more important?

Depending on the cut of your diamond, it will have a more or less significant depth.

If the depth is significant, the diameter of the diamond will be reduced: consequently, less light is reflected to the eye. Therefore, the brilliance and sparkle of the diamond will be of lesser quality.
Conversely, a diamond with less depth will have a larger diameter, therefore, more light is reflected to the eye. Therefore, the brilliance and sparkle of the diamond will be of higher quality.

With this explanation, you can easily understand that it is not the carat that gives the diamond its brilliance, but its cut. By choosing a perfect cut, the gem will appear larger and you can even fool your friends about its weight! It is therefore preferable to prioritize a good cut to the diamond than its carat.

And for the price of the diamond?

The carat, however, has an effect on the price of the diamond. The heavier a diamond, the higher its price. This is explained by the fact that a diamond is cut from a single piece of rough diamond. So to have a 4 carat diamond for example, the piece of rough diamond must be larger than that of a 1 carat diamond. Large rough diamonds are rare in nature, not the smaller ones, the rarer something is, the more it costs. (Fun fact: a ring made up of small diamonds with a total weight of 1 carat is curiously cheaper than a 0.90 carat diamond mounted on a ring, although lighter but also rarer)

Do diamond shapes with the same carats have a different price?

The answer is yes! As a reminder: the shape of the diamond is what will give the most brilliance to the diamond. For example, it is said that the ideal cut of a diamond is a round, brilliant or princess cut. Other so-called fancy cuts retain more weight so fewer rough diamonds are wasted during cutting (higher manufacturing cost). This is why the round cut is the most expensive, the lapidaries had to remove more rough diamond. A fancy cut diamond will cost less than a round cut diamond even if they have the same carat quality. The high price of the round cut is also due to its popularity!

But which carat will save you money?

As with everything, what is popular and famous is more expensive. Many people like to say that they wear a 1 carat diamond on their finger. It's normal! So we can assume that the 1 carat diamond is the most popular. If it is the most popular it means that it is the most expensive, and it is true. Its price difference with a 0.90 carat diamond is for example about 2,000€, it's quite extraordinary to see that the popularity of an object has a considerable consequence on its price. Especially since the size difference of a 0.90 carat diamond with a 1 carat diamond is not striking, you will have trouble distinguishing which one is the largest. (Fun fact: this truth about the diamond has become elle also popular, in 2016 the average carat of a diamond on an engagement ring was 0.90 carat).

Advice from the diamond dealer:

The carat of the diamond is unique to a person. Everyone will choose the weight that pleases them and suits them best. One should not forget the morphology of the fingers for example for an engagement ring.

Many people think that having a diamond that weighs at least 1 carat is THE most important thing and neglect the cut to make the diamond more affordable. We advise you not to do this. The cut is very important to the appearance of the diamond, its brilliance and sparkle. Neglecting this point is like neglecting the unique quality of the diamond.
If you have a small budget, prioritize smaller carats and ask for a cut that will bring out the sparkle of the stone. Make sure you have the best cut for your diamond before deciding on its carat weight. The diamond will be majestic depending on the cut and not its weight.
When buying your diamond it is important to look at all its measurements: depth and table percentages for example.

Congratulations! You are now an expert in understanding diamond carats.