the five c of diamonds chart

When you are in the market for a diamond ring, you need to have a good understanding of the 4Cs to select the right stone and understand what makes a diamond better than another.

Chances are, you probably heard of the four 4Cs (cut, color, carat weight and color) being thrown around if you had done some window shopping or reading up.

But did you know there’s an important extra 5th C you need to consider as well? So, what exactly is it and why does it matter so much when you are making a purchase?

In this write up, we will dive through the 5Cs of buying a diamond and reveal money-saving tips that will help you buy a breathtaking engagement ring without breaking the bank. Read on to find out more about the 5 cs of diamonds …

The First C – Cut Quality

diamond cut most important factor of the 5 cs diamonds

Stunning solitaire ring with super ideal cut diamond – White Flash

Arguably the most important C, cut quality determines the brilliance and sparkle a diamond displays. In the GIA grading lab, a diamond is visually assessed for its light performance, proportions and craftsmanship (symmetry/polish). A grade of Excellent, Very Good, Good, Fair or Poor is then assigned to the stone.

Check out the video below to see a diamond ring from James Allen’s TrueHearts collection with the best of the best cut quality and view it under different lighting conditions.



If you want a diamond that is full of life and vibrant sparkle, you should only buy diamonds that are graded as Excellent (GIA) or Ideal (AGS). You will also need to be discerning and pay attention to the diamond’s proportions and facet precision.

The Second C – Color

In the world of diamonds, the less color a diamond has, the more valuable and desirable it is (with the exception of fancy color diamonds). GIA has created a color grading scale that ranges from D (colorless) to Z (light color) and a grade is assigned by performing a visual comparison against a set of masterstones in the lab.

Most gem quality diamonds that are sold in the consumer market fall into the following categories:

D, E, F – Colorless

G, H, I, J – Near Colorless

K, M – Faint, Slightly Tinted

So, which is the best color to buy? Well, the answer is it depends on your personal preferences and ring style.

I’ve created a video below to compare diamonds across different color grades to show you how they look like in real life. Depending on your own acuity, this video should help you make an informed decision when choosing a color grade for your diamond.



If you are going for a vintage look or a yellow gold setting, J or K diamonds would be good choices. On the other hand, if you need the absolute best of the best, then paying the premium for a D diamond would make sense.

For most people, I recommend the G, H, I color grades because they are practical and offer fantastic value for money. They work well in platinum/white gold settings and will face up white if they are well cut.

The Third C – Carat Weight

Carat weight is the attribute that most people would be familiar with because of its correlation to the visual size of a diamond. Technically speaking, carat weight refers to the metric weight of the diamond and 1 carat is equivalent to 200 milligrams.

Due to rarity in nature, larger diamonds are harder to find and this causes carat weight to have an exponential relation with a diamond’s price. The larger a diamond, the more expensive it is going to be.

The most popular size of a diamond ring is 1 carat because of the psychological, whole number associated with it. The demand for these diamonds creates a price jump from smaller carat diamonds.

Here’s a practical tip that I personally use when shopping on a budget. I tend to look for diamonds that are slightly smaller than the usual “magic numbers” like 1.0ct, 1.5ct and 2.0ct sizes.

For example, I would look within the 0.8ct or 0.9ct range to avoid the price premiums that jewelers place on popular 1ct stones. That’s because a 0.9ct diamond can look very similar to a 1.0ct diamond once it has been set and this can lead to savings of thousands of dollars.

The Fourth C – Clarity

Clarity is an assessment of the inclusions and blemishes found within the diamond that may affect its visual appearance. The gemological lab performs an examination of the diamond under a 10X magnification by a trained gemologist.

Depending on the location, size, quantity, relief and severity of the inclusions, a diamond is then assigned a grade from the following:

FL, IF-  Flawless, Internally Flawless
VVS1, VVS2 – Very, Very Slightly Included
VS1, VS2 – Very Slightly Included
SI1, SI2 – Slightly Included
I1, I2, I3 – Included

Now, it is perfectly normal for natural diamonds to have some form of inclusions due to their chaotic formation process in the Earth. The fewer inclusions a diamond has, the rarer it is. Hence, a higher price premium will be placed on such diamonds.



One common mistake that I see many shoppers make is they get too hung up over getting the highest clarity grade possible as they equate a higher rating to a better looking diamond. In reality, most inclusions are not visible to the unaided eye. A VS2 diamond can look identical to an IF diamond and yet, would cost significantly less.

In the industry, we use a term called “eye-clean” to describe diamonds that have inclusions not visible to the naked eye. Very often, clarity plots found in a grading certificate may look messy and have lots of inclusions plotted but in real life, these inclusions can be minute and don’t affect the diamond’s appearance in any manner.

By eyeballing the diamond physically or with a magnified video, you can find diamonds within the VS2-SI2 range that are eyeclean and allow you to save a lot of money compared to a VVS or IF diamond.

White Flash, James Allen and Blue Nile offer magnified video listings to help you scrutinize the tiniest details of a diamond. Their transparent sales policies also give you complete peace of mind when shopping for an engagement ring.

What is the 5th C And Why Is It Important?

five c of diamonds certification

5 c in diamonds – Certificate.

Some of you might have guessed the 5th C to be Cost or Character or even Confidence but it actually refers to Certificate. The diamond certification (aka grading report) is a document that contains important information on the diamond’s characteristics like the 4Cs, fluorescence and additional comments.

Unethical jewelers will often brush this document off by saying stuff like it’s just a “piece of paper” or “you are buying the diamond, not the paper”.  The fact is, a certificate from a trusted, neutral 3rd party lab like GIA or AGS gives you peace of mind and is an assurance of the diamond’s quality.

This 5th C of buying a diamond validates the accuracy of the 4Cs. If the source of a certificate is unreliable and utilizes questionable grading standards (e.g. EGL and GSI), then the quality of the diamond will likely be “inflated”.

This is the reason why uneducated shoppers fall victim to unethical jewelers who misrepresent their products and end up paying more than what the diamond is actually worth.

The bottom line is, if your jeweler can’t provide you with a reliable diamond certificate, you need to reconsider who you are doing business with and go elsewhere.

Which Are the Grading Labs You Can Trust?

the five c s of diamonds

Perhaps the most pervasive laboratory in the industry is the European Grading Laboratory (EGL). Before they were shut down, diamonds with EGL certificates were notorious for their inaccurate and overly inflated grades which resulted in lots of consumers getting ripped off.

Consumers who bought EGL diamonds and later found out they were duped started filing major lawsuits against their jewelers. This created a storm in the industry and garnered huge media attention to the jewelry industry.

And it didn’t take long before they were banned from major trading networks and went out of business because of their poor grading standards. But the damage was done and millions of consumer dollars were already lost and beyond recovery.

The moral of the story is that you should only buy diamonds that are graded by reliable labs. So, this begs the question. Who are the labs you can trust and should look out for when buying a diamond? I’ve compiled a list below for your convenience:

For lab diamonds, IGI and GCAL. With lab created diamonds, these are the 2 labs that grade on a commercial scale and are what I would recommend in good faith. Personally, I do prefer GCAL because of the light performance data they provide in their certificates. Cutters and jewelers know this. That’s why the better cut diamonds tend to be sent to GCAL for grading while most others get sent to IGI.

For natural diamonds, GIA and AGS. GIA is the world’s foremost authority when it comes to consistent and reliable grading standards. A GIA certificate assures you that you will get exactly what is stated. AGS has similar color and clarity grading standards like GIA but they are stricter when it comes to cut quality. Vendors that deal with high performance diamonds often send their inventory to AGS while most of the generic stones are sent to GIA.

For fancy color diamonds, GIA. The value of a fancy color diamond is largely determined by its hue and saturation. GIA certification is essential because the lab uses sophisticated and advanced equipment to examine a diamond for its origin of color. In the world of fancy color diamonds, the difference between a lab being able to detect any color treatments can equate to hundreds of thousands to millions of dollars.

Let’s Wrap Things Up – 5 C’s of Diamonds

5 c's of rings

Breathtaking halo ring with 0.911ct round brilliant cut diamond.

For first-timers, buying a diamond can be very daunting and confusing. However, if you take a step back and focus on the things that REALLY matter, it will help you make better purchasing decisions.

The key to picking out the right diamond is to find one that fits your budget and style preferences. You don’t need the highest clarity or color grade to get a gorgeous diamond because the key factors that affect a diamond’s appearance are cut quality and carat weight.

The bottom line about buying a diamond is that it needs to be accompanied by a certificate but bear in mind that they are not all created equal. Make sure you only buy a diamond that is graded reliably if you want assurance of its stated quality.

Now that you know what the 4Cs are and the extra important 5th C – certificate, you should be able to use this knowledge to help you pick out a diamond and determine the right price to pay for it. If you still need help with a second opinion or have further questions, feel free to drop me an email. Good luck!

White Flash, James Allen and Blue Nile are 3 reliable retailers that offer a huge selection of GIA and AGS certified diamonds. If you want to get a high quality ring without breaking the bank, make sure you check them out!

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  1. William-
    November 25, 2020 at 9:09 am

    Thanks for writing such an insightful guide on the 5 c’s of engagement rings. I was about to buy a proposal ring from a jeweler that is certified by GAI and initially thought that it was a typo and the ring was certified by GIA. As it turns out, the certificate that was shown to me is from Gemological Appraisal Industry which is based in New York. I was told that the certificate is the same as GIA’s.

  2. Paul Gian-
    November 27, 2020 at 9:43 pm

    I know right? There is a lot of labs with abbreviations that sound very similar to the GIA and those that are trusted by the industry. Besides the 5 cs of diamonds, consumers also need to look at details carefully because some jewelers purposely obfuscate them.

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