The 4Cs of Diamonds: What You Need to Know


Diamonds: they’re the most sought-after precious gemstones, but how does one gauge their quality? Before you buy a diamond, it’s good to educate yourself on the 4Cs of diamonds, where these standards came from, and what they mean to you.

Before the middle of the last century, there weren’t any specific standards people could use to evaluate a diamond. The Gemological Institute of America (GIA) changed all that. The official GIA standards charts were soon adopted throughout the world, and today, they’re the accepted benchmark we use to determine diamond quality and value.

The diamond grading standards are:

  • Diamond color
  • Diamond clarity
  • Diamond cut
  • Diamond carat (weight)


Color-Chart-4cs of Diamonds - Jaume Labro Custom Jewelry

The GIA uses a diamond color scale, rating diamonds with the least amount of color as being the most valuable. It reasons that a pure diamond that contains no other chemical elements will be as colorless as a water droplet.

Color ratings range from D (colorless) to Z (light). The GIA has designated a broader categorization that groups colors into categories. These are:

  • D-F: colorless
  • D-J: near-colorless
  • K-M: faint
  • N-R: very light
  • S-Z: light

You might well be wondering how the GIA distinguishes between colors. After all, they look very similar to us. Gemologists study stones under magnification in controlled lighting conditions to determine their color. With the naked eye, even experts would struggle to differentiate between colors.


Clarity-Chart-4cs of diamonds-Jaume Labro Custom Jewelry

The key to determining the clarity set by GIA is as follows:

  • FL-IF: flawless and internally flawless. No inclusions are visible under 10x magnification
  • VVS1-VVS2: Very, very slightly included. Inclusions are very difficult to see under 10x magnification, even when a trained diamond grader examines the stone.
  • VS1-VS2: Very slightly included. Under 10x magnification inclusions can be seen, but it takes some effort to spot them.
  • SI1-SI2: Slightly included: Inclusions are relatively easy to see under 10X magnification.
  • I1 and I2-I3: Included: It’s very easy to spot the inclusions under 10x magnification. At this point, inclusions begin to affect the brilliance of the diamond.

When diamonds are formed under the earth’s crust, they are subjected to heat and pressure Almost any element present in the earth’s crust can be included in a diamond through ion implantation. When these elements become incorporated into the diamond, they are called “inclusions.” Most diamonds have inclusions of one kind or another, and absolutely flawless diamonds are considered extremely rare and valuable.

Absolutely flawless diamonds are considered extremely rare and valuable. Click To Tweet

That said, most inclusions cannot be seen without magnification because they are so subtle. The location of the inclusion is also important. To standardize the way in which inclusions are evaluated, the GIA created the diamond clarity table.

Along with diamond color, clarity plays an important role in determining value.


In another blog post, we discussed so-called “ideal cut” diamonds, though the GIA doesn’t recognize this term. However, the GIA agrees that good quality craftsmanship on the part of the gem cutter will affect the overall appearance of a diamond. Concurrently, it observes that evaluating the cut of a diamond is a complex process.

Cut-Chart-4cs of diamonds - Jaume Labro Custom Jewelry

To evaluate cut, the GIA looks at the proportions of different parts of a diamond. These proportions determine the following characteristics:

  • Brightness: How much light the diamond reflects
  • Fire: How colors of light are split into a rainbow spectrum when passing through the stone.
  • Scintillation: The pattern of lighter and darker areas which create a diamond’s sparkle.

The GIA diamond cut chart classifies cut into five categories: excellent, very good, good, fair and poor.


“Carat” refers to the measurement of a gemstone, based on its weight. One carat is the equivalent of 200mg. Each carat can be further divided into “points” weighing 2mg each. This allows the GIA to provide a very accurate measurement of a diamond’s weight.

Carat-Chart-4cs of diamonds - Jaume Labro Custom Jewelry

Larger stones would ordinarily be considered more valuable than smaller ones, but color, clarity, and cut play a substantial role in a stone’s worth. For example, a larger stone with a higher weight may cost less than a smaller stone.

Is There a 5th C?

Retailers will often talk about “certification” as being the 5th C, however, the GIA does not recognize this. Although many people refer to GIA diamond reports as “certificates,” this terminology isn’t quite accurate.

The GIA certainly produces reports though, which is one of the most authoritative ways of judging a gem’s value. When purchasing a diamond, you should find out whether you will get a report with the stone so you can be confident of its value.

When purchasing a diamond, you should find out whether you will get a report with the stone so you can be confident of its value. Click To Tweet

The only time this doesn’t apply is when the diamond is very small. With such a stone, the cost of having it evaluated by the GIA will do nothing but inflate its price beyond its true value.

What Do All These Ratings Mean When Choosing a Diamond?

GIA recognizes all gem-quality diamonds as valuable precious stones, but its diamond ratings determine the value of the stone. If you want the most valuable diamond you can get, you would certainly choose a flawless or internally flawless stone that is colorless and has an excellent cut.

Alternatively, you might decide that inclusions which can only be seen under magnification (and with great difficulty) don’t matter to you. After all, once the diamond is set in an engagement ring or fine jewelry item, even a trained jeweler would be hard-pressed to spot any imperfections.

Choose GIA Certified Diamonds from Jaume Labro

At Jaume Labro, we recognize the value of personal choice. What if a GIA top-rated diamond turns out to be much smaller than your budget allows? Some of the distinctions that gemologists make can only be determined in a lab and under magnification! This is particularly true when you look at the diamond color scale and diamond clarity scale. You may even decide that you’d prefer your diamond to have a touch of evident color!

When you choose a stone from Jaume Labro, you have the assurance of knowing that your diamond has been independently valued by the world authorities in the field using GIA Diamond Charts and the 4Cs of diamonds. While personal value may not be quantifiable, Jaume Labro will provide you with original GIA certification that indicates the intrinsic value of your precious stone.

When you choose a stone from Jaume Labro, you have the assurance of knowing that your diamond has been independently valued by GIA Click To Tweet

At Jaume Labro, we want you to help you choose the diamond of your dreams. Our website features an area where you can see just how changes in the 4Cs of diamonds would affect the overall appearance and value of your diamond, allowing you to make an informed choice. Begin by browsing diamonds, or contact Jaume Labro with any questions.