The 4C’s


Robertson and Bach


How to Measure a Diamond’s Value

The Diamond Quality Pyramid is a framework to help you compare diamonds. While all diamonds are precious, those closest to the top of the pyramid — possessing the best combination of cut, clarity, carat weight and color — are the earth’s rarest, most valuable and most beautiful to the eye.

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.

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.



0.25 ct. – 4.1 mm 0.50 ct. – 5.2 mm
0.75 ct. – 5.9 mm 1.00 ct. – 6.5 mm


The Purer a Diamond, the More Brilliant

The greater a diamond’s clarity, the more brilliant, valuable and rare it is — and the higher it is on the Diamond Quality Pyramid.

Virtually all natural diamonds contain identifying characteristics, yet many are invisible to the naked eye. Under the scrutiny of a jeweler’s 10x-magnifying loupe or microscope, natural phenomena — called inclusions — may be seen. These are nature’s birthmarks, and they may look like tiny crystals, clouds, or feathers.

Diamonds categorized as internally flawless reveal no such inclusions. Flawless stones are at the peak of the Diamond Quality Pyramid and are treasured for their rarity and beauty. Diamonds with very, very small inclusions are graded as VVS1 or VVS2. The larger the inclusion, the lower the grade and the less rare the diamond. Inclusions that can be seen with the naked eye are graded I1 or I3.

The number, color, type, size and position of surface and internal birthmarks affect a diamond’s value. Major inclusions can interfere with the path of light that travels through a diamond, diminishing its brilliance and sparkle and therefore its value.

The More Pure the Color in a Diamond, the More Rare

Diamonds are graded by color, starting at D and continuing through the alphabet. Truly colorless stones, graded D, treasured for their rarity and value, are highest on the Diamond Quality Pyramid.

While many diamonds appear colorless, they may actually have subtle yellow or brown tones and these color grades include P and Q. Although still beautiful, they will be less rare and therefore less valuable. To appreciate the simple beauty of each individual stone, you should compare diamonds side by side with a jeweler.

“Fancy” diamonds — in well defined colors that include red, pink, blue, green and canary yellow — are highly prized and particularly rare.

The Better Cut a Diamond, the More Brilliant

A well cut or faceted diamond, regardless of its shape, scintillates with fire and light — offering the greatest brilliance and value.

While nature determines a diamond’s clarity, carat weight and color, the hand of a master craftsman is necessary to release its fire, sparkle and beauty. When a diamond is cut to good proportions, light will reflect from one mirror-like facet to another and disperse through the top of the stone, resulting in a display of brilliance and fire.

Diamonds that are cut too deep or too shallow lose light that spills through the side or bottom. As a result, poorly cut stones will be less brilliant and beautiful — and certainly less valuable — than well cut diamonds higher on the Diamond Quality Pyramid.

Diagram of Diamond Cutting Process.

The Enduring Gift of Love

For centuries, men and women have found that the sparkle and brilliance of a quality diamond expresses their deepest emotions and symbolizes their enduring love. Yet with many beautiful diamonds to choose from — and no two alike — how do you pick the right diamond while spending wisely? The Diamond Quality Pyramid and the 4Cs, along with the guidance of a trusted jeweler, will lead you to the answer.

Diamond Buyer’s Guide

When you start to think about buying a diamond — and the love it will symbolize — you naturally want the best you can afford and a beautiful stone you will treasure forever.

Diamonds can be found in a range of prices — and you’re certain to find one within the Diamond Quality Pyramid that suits your taste and what you plan to spend.

If you’re about to buy a Diamond Engagement Ring, you may want to consider spending the commonly accepted guideline of two month’s salary. But it’s up to you to settle on a diamond that will truly represent your deepest emotions and the promise for the future you will share.

How can you be sure to choose the perfect diamond for her? She may already have dropped hints by admiring a photograph or someone else’s diamond. Browse with her at a trusted jeweler. Share your knowledge of the 4Cs. Later, surprise her with a diamond beyond all her expectations.

When it comes to other types of diamond jewelry, such as a Diamond Solitaire Necklace and Diamond Solitaire Stud Earrings, purchase the diamond that captures the brilliance of the moment. Choosing a quality diamond to celebrate life’s most intimate occasions is a truly rewarding experience for the one who gives as well as for the one who receives.

The 5th C: Confidence

A jeweler who’s a diamond expert can help you select the right stone. Trustworthy jewelers, who establish long-standing relationships with customers, take pride in finding quality diamonds for them. These experts are knowledgeable and accessible and they’re able to explain the 4Cs, as well as show you a selection of diamonds in a range of prices.

While all diamonds are beautiful, only by comparing stones will you be able to appreciate what makes one more rare and valuable than another. When you view stones side by side, you’ll understand why diamonds that look similar at a casual glance are priced differently. Keep in mind that there are no “bargain” diamonds; there are only diamonds of different value, weight and brilliance.

A trusted jeweler can help you choose a diamond shape that suits your personal taste. The classic Round Brilliant, Oval, Pear, Marquise, Princess, Heart and Emerald shapes are among the most beautiful and popular today.

An Occasion Worth Celebrating

Now that you understand why some diamonds are more rare than others, you can make an informed decision. Choose a beautiful stone that combines the qualities of the 4Cs you most value. Then you’re ready to give the most enduring gift of love. Born of the earth, reborn on the woman you love, this diamond is more than a precious gem and all that it symbolizes … it’s a piece of forever.