Diamond’s weigh (Carat)



The diamond’s weight is one of the most important criteria to analyse its rarity

Known as one of the 4C’s, the diamond’s weight is commonly seen like THE factor to determine the diamond’s value. Which isn’t true or false, and here is why.



It is frequent to hear that a diamond is more expensive when it’s bigger. It is true when we look at the diamond from different angles. However, when a client sees a diamond, it usually already is in its setting. Why is it a problem? Mainly because once the diamond is set, the visibility the customer has is limited. Most of the time, it will be easier to observe the upper part of the diamond (table, crown, etc.) Following the ideal proportions, every diamond should be cut with specific angles. Since diamonds can’t always be perfectly cut, some of them have their upper part wider. Unfortunately, some jewelers take advantage of the situation by selling a diamond saying it looks bigger. This said, it causes a misunderstood for the customer since a diamond should never be defined about how big it looks, but about its carat weight.

The diamond’s weight is measured in metric carats. One carat (ct) equals 200 milligrams and since they are tiny, each carat can be divided in 100 points.

Example: .25ct is said: “twenty-five pointers”

Since it can be confusing, the carat for diamonds is not the same as the Karat for gold. They are two complete different measurements. It is also important to mention that: the value we use for different gems vary. The weight is calculated in regards to the density of the stone.

Generally, we calculate quantities with the following technique: If one apple costs 1$, two apples will cost 2$. It is not the same with diamonds. We evaluate the diamond’s cost based on a scale following their carat weight, color, clarity and cut.

Basically, this is how the carat weight explains the rarity of a diamond: If two diamonds have the same color, clarity and cut, but one is 1ct, and the other is 20ct. Which one do you think is the more common to find? The 1 ct. With its volume, it is rarer to find.

Sometimes, a small carat weight change can make a significant price increase.

Example: We have three different diamonds and they all have the same color, clarity and cut.

A) .98 carat B) 1.01 carat C).95 carat

From A to B and C to A, the carat weight difference is the same: .03 carat

Even if in both situations the carat weight difference is the same, their price increase is not. Why? Simply because the diamond “B” is now over 1 carat. We call them the “magic sizes”.

Finally, the carat weight of a diamond is technically unlimited. This is why we need the scales regarding the 3C’s to help define the rarity of the diamond (Color, Clarity and Cut).