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The 1st C: The Carat

For many people, buying a diamond is not an everyday business. It seems quite difficult already. But if you dive deeper in the world of diamonds, it appears even harder to make a choice. How can two seemingly similar diamonds differ so much price-wise? The difference in price can depend on the seller. That's why it is always more beneficial to buy diamonds straight from the source. However, the diamond prices at a diamond store vary as well. This is because a diamond’s value depends on the 4 C’s of diamond valuation. The 4 C’s are carat, cut, color and clarity. The first C to examine in this series is Carat.

Explanation of the first C (Carat) by our Chief Purchasing Officer

Our Chief Purchasing Officer helps you to understand the basics of the 4 C's of diamond valuation. A detailed explanation, you find below this video.


The weight of a diamond

Carat is the weight of a diamond. We use carat actually to express the weight of all gemstones. Carat comes from the French word Carob. Carobs are the seeds of the fruit of the carob tree. These seeds are distributed very evenly and universal weight. On seed weighs on average 0.2 grams.

carob seeds on wooden talbe

Carat indicates the weight of a diamond. But to make it easier for customers and dealers, the carats are divided into points. One carat is 0.2 grams and 100 points. Half a carat is 50 points and weighs 0.1 grams. A quarter carat is 0.05 grams and thus consists of 25 points, and so on. This point system makes it easier and clearer for both the seller and the buyer. The density of a diamond – the specific weight – is 3.2 gram per square centimeter.

The bigger the diamond, the higher the price

It is no surprise that the size (among other things) determines the price of a diamond. The larger the diamond, the more the price (exponentially) rises. This has to do with rarity. Diamonds to half a carat (50 points) are the ones that are most commonly found. Therefore, we consider them relatively ordinary. Diamonds over 0.5 carats are rarer. And diamonds of more than two carats are extremely rare. This causes the price to rise faster as the diamonds become bigger.

The cutting method determines the size of the diamond

The way a diamond is cut, influences the weight of a diamond. A thick girdle (top) or belt (circumference of the diamond), make the diamond a few points heavier. A "steeper" cut diamond, is heavier than a “flatter” cut one. One should always start with assuming that the diamond is cut according to the standardized rules. According to these rules, the diamond has a certain weight. We call this standard is the “ideal diamond cut”. It is not cut too steep and not cut too flat.

Recognizing a fake diamond based on carat

The carat can be a guideline to find imitation diamonds. Because a diamond with a given diameter has a certain weight. If that weight differs much from the norm, it is probably not a real diamond.


Exponential price differences between above and below round carats

Working tool for measuring the size of your diamond

The weight also affects the price in a certain way. For example, 0.99 carat is substantively worth less than a stone of 1.01 carats. This can be as much as a 15% difference in price. That's why a cutter always tries to end just above a round number. He prefers to cut a diamond 1.51 rather than 1.49 and 1.01 over 0.99. The difference between just above and below a round number causes a larger price difference than between, say, a 1.03 and a 1.01-carat diamond.

How many carats is my diamond?

Each diamond shape has a different formula to calculate the carat of a diamond. The formula to calculate the weight of a brilliant cut diamond is:

Height x diameter ² x 0.0061

This is according to the standard. A large difference is an indication of bad polishing or an imitation. Every kind of cut has its own formula to calculate the weight. So there’s a different one for emerald cut, heart shaped diamonds and a princess cut for example.

different carat sizes

Weighing a diamond with a scale

Today, we weigh diamonds with an electronic scale. Before, we used a mechanical one. With an electronic scale, weighing is a lot more accurate. It is even possible to calculate up to the 3rd digit after the decimal place. The scale that is used to weigh diamonds should be checked at least once a year by an official qualified company. Preferably, multiple times a year.

Diamond weighing for free

It remains always difficult to determine the weight or the carat of a diamond yourself. Therefore we encourage you to visit our store in Amsterdam. Our diamond polishers are happy to weigh your diamond for you. You finally know exactly how many carats your diamond is. Combine your visit with a diamond factory tour or book a Diamond Masterclass to learn everything about diamond evaluation. In the Masterclass, you will learn among other things, how to determine a diamond’s carat yourself and about the 4 C's of diamond valuation. Read about the other C's:

The other C's:

> The second C, Color
> The third C, Clarity
> The fourth C, Cut