The 4 C’s of Diamond Engagement Rings (The Ultimate Guide)

We’re sure you’ve heard of the “4Cs” before. It’s one of those terms you’ve heard bandied around when you are thinking of getting engaged.

Your friends and relatives will tell you that when you go to buy an engagement ring you that should be thoroughly versed in the ins and outs of this seemingly technical term, but as you are probably not a gemologist, how are you supposed to suddenly become an expert in judging the quality of a diamond?

Let’s face it, most diamonds look alike, apart from their size, don’t they?

Because it is such an expensive purchase, however, you’ll want to educate yourself.

What are the most important things to consider when buying a diamond? How can you trust the quality of what you are buying? Before we delve into what the 4Cs actually are, we’ll tell you how to feel more comfortable about your purchase.

The answer is – you should always buy a diamond that has been independently verified and certified by a third-party organization, one that earns nothing from the sale.

A grading report or certification from a reliable source can save you from buying a diamond that has been artificially treated for color or clarity or one that is synthetic or worse still, fake!

There are several organizations who grade and certify diamonds, but there are only two we recommend:

  • The Gemological Institute of America (GIA) is an independent non-profit organization protecting you, the diamond purchaser, with unbiased scientific research, education and laboratory services. They are the authority on diamond quality and can steer you in the right direction, giving you the confidence to avoid costly and potentially embarrassing mistakes. Founded in 1931, GIA is the world’s foremost diamond authority and is the globally accepted standard by which all diamonds are judged. Those who deal in the world’s best diamonds rely on GIA to accurately assess and identify their quality characteristics.
  • The American Gem Society (AGS) was founded in 1934 by a small group of leading jewelers to protect the purchasing public from fraud and false advertising. The AGS is smaller than the GIA and they made their name by pioneering the area of diamond cut quality analysis (one of the 4Cs), thought the use of ray-tracing technology which measures the light performance of a diamond. It is said that AGS offers a stricter cut quality analysis that GIA. Today there are approximately 3,400 jewelers, retailers and suppliers who are members, dedicated to upholding ethical business practices.
  • The AGS uses a scale of 1-10 for rating a diamond’s characteristics, with 0 the best and 10 the worst. The AGS’s 0-10 scale parallels the GIA’s alphabetical 4C scale, which is divided in smaller categories for a more finite reflection of each diamond’s quality measurement.

What Are the 4Cs? What Do I Need to Know About Them?

It was GIA that created the first system to accurately reflect diamond quality, known as the 4Cs.

These are Color, Clarity, Cut and Carat Weight.

GIA also developed the first International Diamond Grading System™, which is a scientific method for evaluating and describing diamond quality using the 4Cs.

With a GIA Diamond Grading Report™ in hand, you can have confidence in what you are buying, because it is a scientific and unbiased blueprint of your diamond’s exact quality characteristics. GIA offers strict grading and proven consistency in their certification, so they are trusted the world over.

A diamond’s 4Cs represent both its beauty, quality and therefore its value. Each of the 4Cs is graded on a scale which helps determine its value before the retailer adds their markup.

Here are details about the 4Cs and what they measure:

1. Color

It is actually the absence of color that distinguishes the purest of white diamonds.

The rarest stones have little or no color at all. This is not to be confused with “fancy” colored diamonds which can come in a variety of shades such as pink, chocolate, yellow and even blue; these are considered different and are graded on a separate scale.

However, in a white diamond, the presence of a yellow tint greatly lowers its value, so the less body color it has, the greater its value and market price.

A diamond’s color is developed as part of its natural composition. It is caused by the trace elements which are present when the diamond is forming underneath the earth, and it is extremely rare to find one that is completely “white.”

For a diamond to give its characteristic brilliance, which is called dispersion or “fire,” it needs to be just about color-free so that more light can pass through it.

Light passing through a diamond is divided into a spectrum of color, like a prism, so a diamond with the lowest level of color which allows the maximum possible light penetration, will throw off a more colorful “fire.”

If you’ve looked at a good quality diamond and see the prism of colorful light sparkle when the ring is moved, you’ll know exactly what we mean.

GIA has developed an international industry standard for color which goes from D, which is the highest quality and virtually colorless, to Z, which is likely to have brown tones and is not even offered by most retailers.

  • D: Totally colorless. The highest possible grade. Very rare and expensive.
  • E: Considered colorless but has traces of color which can be detected by an expert. A high- quality diamond.
  • F: Still considered colorless, but an expert can detect color traces. A high-quality diamond, nevertheless.
  • G-H-I-J: Nearly colorless and still good value.
  • K-L-M: Faintly tinted, usually yellow.
  • N-O-P-Q-R: Lightly tinted in progressively darker tones of yellow. Color can be seen with the naked eye.
  • S-T-U-V-W-X-Y-Z: Tinted, usually yellow, may progress to brownish. Visible to the naked eye.

In most cases, you’ll find it difficult to see the difference between two adjacent color grades, although the price difference may be substantial.

What Color Grade Should You Choose?

For great value and quality, start with G or H grade diamonds which are nearly colorless.

Here are a couple of pointers related to diamond color:

  • For a diamond under 1 carat weight, you can get away with an I, J or even a K rating because the stone will not be big enough to notice a slight coloration.
  • However, if you are going for a diamond of over 1 carat, it is better to go for an H-grade colorationor higher because the larger size will show the color more.
  • The most important thing to remember about color is how the diamond looks in relation to its setting. A lesser quality diamond in terms of color – i.e. with a yellowish tinge, will look dull against a white gold setting, however it may look completely acceptable in a rose or yellow gold setting.

2. Clarity

The clarity or cleanliness of a diamond is all about the number and type of its structural flaws. These flaws are often microscopic so you may not even notice them.

Natural diamonds are formed from the exposure of carbon to tremendous heat and pressure deep in the earth and they are completely natural. They are created when foreign material, structural irregularities, tiny cracks called “feathers” appear during the formation process of the gem.

The flaws within the diamonds itself are called “inclusions” and flaws on the outside of the diamond are called “blemishes” and they are what make each gem totally unique.

The least flawed or “included” diamonds are obviously the most highly prized and therefore the most expensive.

It is the size, the location and the darkness of these inclusions and blemishes that will determine the final clarity grade of your diamond because these imperfections can reduce the light passing through it, making the stone look duller and less brilliant to the eye.

An FL (Flawless) diamond with few or no inclusions is considered very rare and is highly prized, therefore very expensive.

The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades:

  • Flawless (FL)No inclusions and no blemishes visible under 10x magnification
  • Internally Flawless (IF)No inclusions visible under 10x magnification
  • Very, Very Slightly Included(VVS1 and VVS2) Inclusions so slight they are difficult for even a skilled grader to see under 10x magnification
  • Very Slightly Included (VS1and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor
  • Slightly Included (SI1and SI2) Inclusions are noticeable under 10x magnification
  • Included (I1I2, and I3)Inclusions are obvious under 10x magnification which may affect transparency and brilliance

What Clarity Grade Should You Choose?

Let’s put clarity in perspective.

Most diamonds have tiny flaws that you will not be able to see without magnification. A good place to start looking if you are trying to maximize your budget is with S12 and S11 grades.

Remember also that weight affects clarity, so if your diamond is under 2 carats, we recommend you go with VS2 grade.

Unless you have an unlimited budget and are going for a top-of-the-line gem, you do not necessarily have to go for Flawless. There are stunning diamonds with lower clarity grades.

A diamond with VVS and VS grading can still look magnificent but is a lot easier on your wallet.

SI1 and SI2 diamonds will not have any visible blemishes or inclusions that can be seen by the naked eye and they are more affordable still. These are what gemologists call “eye clean” which means you cannot see any flaws with the naked eye.

Whatever you choose in terms of clarity, it is always possible to place more emphasis on one of the other Cs, if you determine that carat weight or cut is more important to you.

Clarity, in general, has the least impact on a diamond’s appearance and overall beauty so it is worth remembering that even if you decide to choose a stone with small inclusions, they will be totally invisible to all but the gemologist – and you will still have a stunning ring you can be proud of.

3. Cut

You may be surprised to learn that the most critical factor in determining the value of a diamond is considered by experts to be its cut (not carat weight as most people initially think).

The overall appeal, symmetry and value of a diamond are largely determined by the quality of its cut. Of all the diamond 4Cs, the cut is the most complex and technically difficult to assess.

Cut is not the same as shape, by the way.

The cut, or “make” of a diamond has a direct link to its value and appeal; an expert diamond cutter can bring out a stone’s beauty with a clever balance of symmetry, facets, proportion and polish.

When a diamond has been well cut, it is able to both reflect and refract light, so understanding the way light moves is a critical part of the cutter’s art.

Specific facet cuts and proportions have been developed by experts over the centuries to make the most of each diamond. Simply put, the better the cut, the more light is directed towards the eye.

An expertly cut smaller diamond may in fact, be worth more than an oversized one. Similarly, a well-cut stone will often appear larger that a diamond of the same carat weight and it will look as if it has better color and clarity.

The grade of a diamond’s cut is composed of three different kinds of light reflection:

  • Dispersion or Fire – Dispersion refers to the spectrum of colors that is reflected to the eye from the diamond, like a spectrum of colors in a rainbow. When light enters the diamond, it is broken down and reflected around its interior, bouncing off its facets and then leaving through the crown of the gem. The colors stay separated and reach the eye in brilliant flashes of glorious colors. This dispersion is a highly prized feature of a top-quality diamond.
  • Brilliance – This refers to the degree of whiteness or brightness of the light that exits out of the diamond reflecting back to the eye.
  • Scintillation – This is the play of light you will see when a diamond is moved. It is a sparkling or glittering effect on the diamond’s surface which represents both a reflection and refraction of light. The balance of these three types of light reflection that make a true top-quality diamond. The best-cut diamonds have proportions that maximize their light dispersion, brilliance and scintillation and so the grading scale for cut is based upon this very delicate equation.
  • Remember – a poor cut (i.e. too shallow or too deep) can make even a flawless diamond look dull because the light will not pass through it as well as with an excellent cut. That is a waste of your money.

The GIA Diamond Cut Scale

  • Excellent: Representing the top 1% tier in diamond quality based on cut, polish and symmetry. Outstanding stone with an even pattern of bright and dark areas.
  • Very Good: Represents approximately the top 3% in diamond quality. Proportions have led to some darkness.
  • Good: Represents approximately the top 15% in diamond cut quality. Limited scintillation.
  • Fair: Represents roughly the top 25% in terms of diamond cut quality. Lacking contrast and with general darkness.
  • Poor: Represents diamonds that are cut too deep or too narrow and shallow, so they lose light out of the sides and bottom. Mediocre. These are the least expensive diamonds of all.

4. Carat

Carat is the word most often associated with the purchase of a diamond and is a commonly accepted term. However, did you know that a diamond’s carat measurement refers to its weight and not its size?

The modern carat system actually started with the carob seed. Early gem traders used the small, uniform seeds as counterweights in their balance scales. The carat is universally accepted as the same gram weight in every corner of the world.

A carat (not to be mistaken with the word karat, which determines the purity of gold) is a unit of weight specifically for diamonds and is equivalent to 200 milligrams.

Carat weight is commonly expressed in points or fractions and one carat is equal to 100 points, so each point is equivalent to 100th of a carat (0.01). Other types of gemstones are also measured by carat weight, but different gems of the same weight are not necessarily the same size because they have different levels of inherent density.

If you are wondering whether size really does matter when buying a diamond, remember that larger diamonds are rarer and more in demand, so diamond prices tend rise in conjunction with carat weight.

A 1.00ct stone will be more expensive than two .50 ct diamonds of the same quality. Double the weight of a diamond, generally speaking, and you quadruple its cost.

As a rule of thumb, multiple smaller stones weighing as much as one larger stone will always cost less even though they weigh the same, which does not seem logical. On the other hand, two diamonds of equal weight may have different pricing if their clarity and cut are not of equal quality.

Here are some other pointers about carat weight:

  • The letters TWC refer to Total Carat Weight, which is the combined diamond weight of a ring with multiple gems. For instance, a halo ring, which consists of a halo of smaller diamonds surrounding a larger central one, may be quoted in TWC because it consists of multiple diamonds.
  • Some weights are considered “magic sizes” – half carat, three-quarter carat, and carat. Visually, there’s little difference between a 0.99 carat diamond and one that weighs a full carat. The price difference between the two can be significant as the .99 carat diamond is considerably cheaper.

Here’s a good tip: If size really is your thing, fancy shaped diamonds – such as Princess, Asscher, Emerald, Marquise, Oval, Radiant, Pear, Heart and Cushion generally cost less per carat than an equivalent round diamond. These shapes can also appear larger than their actual carat size especially when placed in a halo ring setting.

Which of the 4Cs Is the Most Important?

That’s up to you and the budget you have set for yourself – and what she has set her heart on.

Her preferences are critical unless you want a disappointed fiancée. You need to find out what SHE wants. If you’ve done your homework on this, you’ll know what your 4C priorities should be and you can work them into the equation.

If she wants a rock and therefore carat weight is your number one priority, then go for the largest diamond you can afford, given that you’ll have to compromise on its color, clarity and cut.

However, if she wants a flawless diamond, then you may have to compromise on the other 4Cs. Alternatively, you can decide if a balance of all 4Cs makes the most sense for you both.

Here’s a quick note of advice:

Start with Cost – (the 5th C!!) Decide on your budget and STICK WITH IT

Carat weight critical? Scale back on Cut, Color & Clarity

Cut crucial? Scale back on Carat, Color & Clarity

You get the picture.

Blue Nile has an interesting way to decide which of the 4Cs is the most important. They recommend you “think with your eyes.” Decide where to spend your money and where to prioritize, based on what you first see when you look at a diamond.

  • You’ll see the sparkle first, so your priority needs to be on a great cut
  • Next, to appreciate the color, you’ll need to get closer
  • To see the stone’s clarity, you’ll have to get 6”-8” inches away – or use a jewelers’ loupe

Get Your Diamond Third Party Certified

Finally, we recommend you make sure to ask your jeweler or online retailer for your diamond’s GIA or AGS Certification Report before purchase, so that you can be sure you understand exactly what you are buying.

If you are still doubtful about your diamond’s quality and authenticity, you can even send it directly to GIA who will grade and analyze it for you, or have your retailer send it on your behalf so they can handle the shipping and insurance.

Remember that GIA only analyzes unmounted diamonds so have it sent to them before it is put into your chosen setting. If not, they will, carefully, take it out of its setting before grading it. 

Why do we think a GIA Diamond Grading Report™ so important? It is the only universally accepted, unbiased assessment of your diamond’s overall 4C grading.

A GIA Diamond Grading Report™ not only provides expert analysis of color, clarity, cut and carat weight, it also contains a diagram that clearly shows a diamond’s inclusions and clarity characteristics.

All GIA reports contain security features such as a hologram, security screen and microprint lines that prevent them from being forged or duplicated – and your GIA report can also be used for insurance purposes and to identify a lost or stolen diamond, if you are unlucky enough to lose it. 

The Bottom Line

Buying the right diamond for your engagement ring depends on your budget and your (and her) taste. You will want to get the best diamond you can afford, but there will have to be trade-offs.

Knowing your priorities in the first place – and sticking with your budget- will save you both a lot of heartache and disappointment.

So, there you have it – Color, Cut, Clarity and Carat Weight – the 4Cs explained. It’s really not that complicated, so don’t be unnerved. 

Take a deep breath, think logically, stick to your budget and your priorities and it will all make sense.