Robertson & Bach Fine Jewelers

THE 4Cs
Key to the Diamond Quality Pyramid
To establish a diamond’s quality, jewelers examine each of the 4Cs — cut, clarity, carat weight and color. The combination of the 4Cs determines the value of a particular diamond. For example, a colorless diamond is at the top of the Diamond Quality Pyramid in color … but if it lacks clarity, is small, or not well cut, it will be of a lower value. The finest stones possess the rarest quality in each of the 4Cs, and are the most valuable.
Strive for a stone that offers the best combination of the 4Cs. Knowing a diamond’s place in the Diamond Quality Pyramid will help you to make an informed decision. Ultimately, you’ll discover the unique combination of the 4Cs that makes a particular diamond the right choice for you. Its beauty and brilliance will capture the true sentiment of the occasion.
CARAT
The Larger a Diamond, the More Rare
Larger diamonds are found relatively infrequently in nature, which places them at the rarest level of the Diamond Quality Pyramid. What also makes a bigger diamond so desirable is that it shows off a stone’s fine color and cut, and therefore its brilliance, to its best advantage.
A diamond’s size is measured in carat weight, and each carat is equal to 100 points. A .75 carat diamond is the same as a 75-point diamond or a 3/4 carat stone.
While larger diamonds are highly prized, diamonds of equal size may vary widely in value and brilliance, depending on their qualities of clarity, cut, and color.
The size of a diamond has the biggest impact on its price. The metric carat, which equals 0.20 gram, is the standard unit of weight for diamonds and most other gems. If other factors are equal, the more a stone weighs, the more valuable it will be.
Here are several ways to express 1 carat:
1 ct.
200 milligrams
1/5 gram
100 points
4 grainer (not often used in retail environment)
It is very important not to mistake carat weight as referring to the dimensions of a diamond. It refers to weight only. Why the distinction? Because weight can hide in different parts of the stone. You can have a) well-cut, b) deep, or c) shallow Diamonds. Some may appear larger than others due to its cut.
Prices of diamonds are expressed in the trade as a price per carat. So when we say that the Carat Weight has the biggest impact on the price of the stone, we refer to the unit price per carat, not just the overall price of the whole stone.
Example 1:
Diamond “A” = 0.25 carats and costs $1,000 per carat. $1,000 x 0.25 = $250/stone.
Diamond “B” = 0.50 carats and costs $1,250 per carat. $1,250 x 0.50 = $625/stone.
It is very common for people to disregard the other C’s in favor of getting the biggest possible stone they have budgeted for. Although SIZE DOES MATTER, we feel it is just as important for the quality of the stone to be high.
Some people may feel it is more impressive to wear a 2 carat diamond than a 1 carat diamond. But that’s not necessarily true. A Ferrari may not be as big a car as an Oldsmobile, but most would consider it more impressive.
How “big” is a carat?
Many people would like to “understand” carat sizes in real terms. Here’s a simple trick to get an idea. Simply take a ruler, and look at the table below. These are some approximate, sample carat-weight to diameter-widths for popular sizes.