4Cs Diamond Guide

The 4Cs of Diamond Buying

Here at Bailey’s, we have been in business for over 70 years and we know a thing or two about buying a diamond. We want to pass our knowledge on to you so that when it’s time for you to make your purchase, you can feel confident about what you’re getting. The most important and universal scale of evaluating diamonds is the 4Cs: cut, clarity, color, and carat. We like to say that the 4Cs are a sliding scale when it comes to purchasing a diamond! It’s all about determining which elements of the diamond are most important to you and adjusting the other elements to get what you want within your budget. With knowledge of the 4Cs, you can be sure that you’re getting a great deal at any jewelry counter.

The 4Cs of Diamond Quality


Cut refers to the proportions, internal fascets, and symmetry of the diamond.


Color ranges from D, completely colorless, to Z, slightly yellow, and determines the warmth of the diamond.


Clarity measures any visible imperfections in the diamond and is an indication of its rarity.

Carat Weight

Many think that carat refers to the diamonds’ size but carat is a measurement of weight, not size.


The art of cutting and polishing is where a diamond truly achieves its greatness. Fine diamonds are produced by the precision and skill of the world’s finest cutters.

A polished diamond’s beauty lies in its complex relationship with light – how light strikes the surface, how much enters the diamond, how much light leaves the diamond, and what form of light returns to your eye. The result is a magnificent display of three attributes:

  1. Brightness is the combination of all white light reflecting from the surface and interior of a diamond.
  2. Fire describes the “flares” of color emitted from a diamond.
  3. Scintillation describes the flashes of light you see when the diamond, the light, or the observer moves! This is commonly known as sparkle.

A polished diamond’s proportions directly affect these three elements, which in turn affects its beauty, and overall appeal. Diamonds with fine proportions, symmetry, and polish optimize their interaction with light and have increased brightness, fire, and scintillation.


Although many people think of diamonds as white or colorless, truly colorless diamonds are actually very rare. Most diamonds used in jewelry are nearly colorless with tints of yellow or brown.

Color grades are determined by comparing each diamond to a master set. A diamond’s color is most accurately determined when it is not mounted in a setting. One reason for this is that the setting can introduce tints of its own color into the diamond. Think about setting a diamond in yellow gold – you would be able to see the warm tones from the gold reflecting through the diamond. Color can also be determined by the cut as well-cut diamonds can look up to two color grades better.

Diamonds also come in colors that are not graded on the D-Z scale such as blue, pink, purple, red, green, orange, brown, and yellow. These are commonly referred to as ‘fancy’ colored diamonds and are made possible by different elements incorporating themselves in the chemical makeup of the diamond. These diamonds, if natural in color, are even rarer than traditional white diamonds and can be even more expensive.


Due to the tremendous heat and pressure under which diamonds are formed, different internal or external characteristics can be included in the diamonds’ makeup causing them to look imperfect either under powerful magnification or to the naked eye.

These characteristics are a byproduct of the diamond’s formation and help gemologists separate natural diamonds from man-made forms like lab-grown diamonds! They also act as identifiers because these characteristics, called inclusions, are like the diamond’s “birthmark” and are completely unique to each gem. In most cases, the presence of inclusions does not reduce the diamond’s beauty or durability because they cannot be seen to the naked eye. Less than 1 percent of all diamonds have no inclusions and can be deemed flawless (FL) or internally flawless (IF), making them super rare (and expensive!)

The scale of clarity goes from “Flawless”, meaning that there are no inclusions under 10x magnification, to “Very Very Slightly Included”, meaning that inclusions are difficult to identify under 10x magnification, and cannot be seen by the naked eye. Next, “Very Slightly Included”, meaning that a skilled grader could easily identify inclusions under 10x magnification but not by the naked eye, to “Slightly Included”, which means that inclusions are very noticeable under 10x magnification but not to the naked eye. Lastly, “Imperfect” means that inclusions are easily recognizable by the naked eye and they could affect the brilliance of the diamond.

Carat Weight

A diamond’s carat weight is exactly that… its weight, not its size. For example, when comparing two 1-carat round diamonds, it’s possible for them to look completely different in size due to the cut and proportions of the diamond! Diamonds have “optimized” cuts, meaning that if two 1-carat diamonds of the same shape are looking like completely different sizes, one is likely more optimally cut than the other.

If diamonds are cut too shallow, it might make them look bigger, but it reduces their sparkle. If diamonds are cut too deep, it might look smaller in size because it’s going to carry more of its weight in the lower portion of the diamond. It’s important to strike a balance between cut and carat when buying a diamond to be sure that you’re getting a high-quality gem.

Fun fact: The word carat comes from the word carob (as in carob seeds) which is how ancient cultures measured the weight of diamonds on their scales. In 1913, the weight was standardized internationally and adopted the metric system. One carat equals 200 milligrams. For diamonds under one carat, each carat is divided into 100 points. (like pennies in a dollar. 075 ct. = 75 points, .5 carat = 50 points).



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