Three differently cut lab-grown diamonds, one heart shaped, one round and one cushion cut on a black background for the 4 C's of diamond grading.

The 4 C’s of Diamond Grading: A Complete Guide

Diamond jewelry invokes a sense of tradition, sophistication, and luxury. Long the favored stone for engagement rings and wedding bands, diamonds are precious ornamentation that symbolize love and commitment and impart strong emotional ties. Our Complete Guide on the 4C’s of diamond grading explains how carat, color, clarity, and cut determine the value of individual gems. It will help you decide on the best diamond stone to buy for your jewelry design.

Why is Diamond Grading Important?

To the inexperienced eye, telling a genuine diamond from a zircon or a top stone from a poor one isn’t easy. The diamond grading system is a worldwide process of proving two essentials:

  • Firstly, that the gem you’re buying is an authentic diamond, and
  • Secondly, what the precise characteristics of an individual stone are so that its value can be fairly determined.

The four characteristics (the 4 C’s) of diamond stones are ranked in the order of Cut, Color, Clarity, and Carat Weight. The American Gem Society describes a ten-point ranking system, grading diamonds from the top level of Ideal to the lowest level of Poor.

Before you outlay your hard-earned cash on diamond jewels, it pays to understand the 4 C's in a little more detail. This knowledge will help ensure you’re buying the best quality stones that align with your budget.

1. The Cut of a Diamond

Diamonds can be cut in many shapes — round, oval, pear, and heart, being just a few. However, the cut of a diamond doesn’t refer so much to the shape as it does to how the stone is faceted. Precision work with specialized tools takes the natural angles and symmetry of an individual gem, and using sawing, grinding, and polishing techniques brings out the gem’s brilliance.

A diamond’s cut is a critical factor in determining its value. This is because the cut determines how the diamond interacts with light, i.e., its brilliance, fire, and scintillation. The classic sparkle of diamonds is their most prized quality.

The cut of a diamond refers to the way light is reflected through each facet and angle. The higher a diamond’s cut, the more light returns to the eye, and the more appealing it’s appearance and quality. A diamond’s cut is graded on a scale from excellent to poor.

If a diamond is cut too shallow, the light escapes through the pavilion:

diamond cut too shallow diagram

If a diamond is cut too deep, the light escapes through the opposite side of the pavilion:

Diamond cut too deep diagram

If a diamond is cut to good proportions, the light is reflected from one facet to another and then dispersed through the top of the stone. This is what affects a diamond’s overall sparkle:

perfectly cut diamond


2. Diamond Color

A completely transparent white sparkling stone is the general perception of how a diamond should appear. However, diamonds come in quite an astonishing range of colors. From light yellow to deeper shades of brown, blue, green, and pink, diamonds naturally occur across the color spectrum.

Differen Diamond Colors

A diamond’s color is another critical basis of value and a key element in diamond grading. Clear, transparent diamonds with little color are highly valued. Also known as white diamonds, they are the traditional stone for engagement rings and wedding bands.

However, some tones and shades outdo white diamonds in value. For example, market conditions for Australian natural pink diamonds have resulted in valuations of up to 20 times the value of an equivalent white diamond.

3. Diamond Clarity

Clarity refers to how clear and transparent a stone is, along with any internal or external blemishes. Inclusions are marks under the gemstone’s surface, often caused by indents or holes. These imperfections are mostly too small to see with the naked eye and are present in almost all diamonds. Stones with visible inclusions will receive a much lower quality grading compared to gems with only microscopic flaws.

4. Carat Weight

Carat is the term for the unit of weight for diamonds and other gemstones. One carat is the equivalent of 0.200 grams or 1/5 gram. The weight of a diamond helps determine the value of like-to-like gem categories. So, a 2-carat white flawless diamond will be exponentially higher than a similar 1-carat diamond. But a 2-carat yellow will have a lesser value than a similar quality 2-carat white diamond.

Diamond Sizes

Choosing carat weight is all about the design you’ve chosen. For example, if you want a center stone to be highly visible, you’ll need the stone to have the appropriate dimensions. However, using small diamonds along a band can opt for much smaller carat weights.

Carbon Diamonds’ Additional 3 C’s

Before picking your perfect diamond, there are 3 additional C’s to consider in your decision making process: 


When comparing the cost of two identical diamonds, one mined and one lab-grown, the prices differ greatly. A 2.00ct Round Brilliant Cut Triple Excellent Mined Diamond costs about $47,500.00. A ​​2.00ct Round Brilliant Cut Triple Excellent Carbon Diamond costs only $4500.00. Although these diamonds are of equal quality, the productions costs are incredibly different when mining verses manufacturing. Spend your money wisely, and consider a lab-grown diamond. 


Carbon Diamonds is a leader in the scientific diamond evolution. We provide stunning Lab-Grown Diamonds as an eco-conscious and humanitarian alternative to traditionally earth-mined stones. We are dedicated to education and information sharing in the hope that customers will demand more from retailers, and the jewelry industry at large will follow our lead. We source high-quality manufactured diamonds from reputable laboratories who continuously strive to reduce their carbon footprint for our exquisite range of jewelry.

Customize Your Own Bespoke Diamond Jewelry Designs

Now that you understand how diamond grading on cut, color, clarity, and carat weight work together to determine price and value, you’re in an excellent place to start looking at design. At Carbon Diamonds, we can give you a free design consultation to start you on the path to creating your own unique designs.

After your design consult, we will develop sketches and computer-aided designs to give you several design options. We then work closely with you during every step of the design and creation process. Finally, our expert goldsmiths and jewelers will create your piece, metal casting, and set the stones to your delight. Get in touch to schedule your in-store or virtual design session. 

For those interested in learning more tips & industry secrets, we highly recommend a no-obligation Diamond Lesson with one of our Diamond Experts. We can do this in person or via Zoom Video conferencing. The more you know will ultimately make your selection easier and more cost-effective. Investing 30 - 45 minutes of your time will give you the confidence to make an intelligent choice.