4Cs Diamond Guide

What's Most Important When Buying a Diamond?

Bailey’s wants you to be confident when buying your diamond. We’re diamond experts and we can teach you all about the 4Cs of diamond quality and everything you need to know about buying a diamond before you buy an engagement ring. If you’ve ever wondered,”what are the 4Cs?” keep reading!

The 4Cs of Diamond Quality


Cut refers to the proportions and symmetry of the diamond.


Color grades are determined by comparing each diamond to a master set.


Clarity is an indication of a diamond’s rarity.

Carat Weight

A diamond’s carat is its weight, not its size.


It’s All in the Cut. The art of cutting and polishing that a diamond truly achieves its greatness. Only with the precision and skill of the world’s finest cutters are truly fine diamonds produced.

A polished diamond’s beauty lies in its complex relationship with light – how light strikes the surface, how much enters the diamond, and how, and what form 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.

A polished diamond’s proportions affect its light performance, 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 gem quality diamonds as 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. Also, the grader should view the diamond from the pavilion (the bottom) because the true color of a diamond can be “masked” by a high-quality cut. Diamonds with superior cut and polish can look up to two color grades better when viewed face up. For these reasons, gemological laboratories such as the Gemological Institute of America (GIA) and the American Gem Society (AGS) will only grade diamonds un-mounted.

Diamonds also come in colors such as blue, pink, purple, red, green, orange, brown and yellow. These are commonly referred to as ‘fancy’ colored diamonds. These diamonds, if natural in color, are even rarer and can command very high prices.


Clarity is an indication of a diamond’s rarity. In almost all diamonds, except the most rare, there are internal and/or external characteristics. This is due to the tremendous heat and pressure under which diamonds are formed. These characteristics are a byproduct of the diamond’s formation and help gemologists separate natural diamonds from synthetics and simulants. It also helps identify individual diamonds because these characteristics, called inclusions, act as the diamond’s “birthmark.” The presence of some inclusions does not diminish the diamond’s beauty or endanger its durability. The outer beauty of a diamond comes from the cut and color. In fact, most inclusions require powerful magnification before they are visible. Less than 1 percent of all diamonds have no inclusions and can be deemed flawless (FL) or internally flawless (IF).

  • Flawless(FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
  • Internally Flawless(IF) – No inclusions and only minor blemishes are visible to a skilled grader using 10× magnification
  • Very, Very Slightly Included(VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10× magnification
  • Very Slightly Included(VS1 and VS2) – Inclusions are clearly visible under 10× magnification but can be characterized as minor
  • Slightly Included(SI1 and SI2) – Inclusions are noticeable to a skilled grader using 10× magnification
  • Imperfect (I1, I2, and I3)– Inclusions are obvious under 10× magnification and may affect transparency and brilliance

Carat Weight

A diamond’s carat weight is exactly that… its weight, not its size. Be aware of this when shopping for a diamond. For example, when comparing two 1 carat round diamonds, one might look much larger or smaller that the other. This is due to the cut and proportions of the diamond. A well cut 1 carat round diamond should measure approximately 6.5 millimeters in diameter. If it’s too shallow, the diamond will have a broader diameter making it appear larger, but very dull. The same is true for a 1 carat diamond that is cut too deeply. It will appear smaller when compared to a well cut 1 carat diamond and will pale in comparison in beauty. The saying is true, “You get what you pay for.”

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 stadardised internationally and adapted to the metric system. One carat equals 200 milligrams. For diamonds under one carat, each carat is devied into 100 points. (like pennies in a dollar. 075 ct. = 75 points, .5 carat = 50 points).



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