The Complete Guide to the 4 Cs of Diamonds

Q: How do the 4Cs collectively impact a diamond's price?

Each of the 4 Cs plays a role in a diamond’s value:• Carat and cut usually have the most impact on price.• Color and clarity affect price less when staying within near-colorless and eye-clean ranges.Together, the 4 Cs determine rarity, beauty, and market value. Even small upgrades in one category can significantly affect price — especially around “magic” carat sizes (like 1.0, 1.5, 2.0 carats).

In This Guide

What Are the 4 Cs of Diamonds?
Diamond Cut
Diamond Color
Diamond Clarity
Diamond Carat
The Interplay of the 4Cs
Four Cs of Diamonds FAQs

When it comes to choosing the perfect diamond, the Four Cs — Cut, Color, Clarity, and Carat — are your foundation. Originally developed by the Gemological Institute of America (GIA), this system helps you understand what makes a diamond beautiful, valuable, and unique.

Whether you are purchasing a lab grown diamond engagement ring, fine jewelry, or simply considering your options, you will want to know how the 4Cs work (both individually and together) so you can make a knowledgeable and confident decision.

What Are the 4 Cs of Diamonds?

The 4 Cs are Cut, Color, Clarity, and Carat Weight. Combined, these four aspects create a universal language for diamond quality - allowing expert and consumer buying decisions to be evaluated and compared consistently!

Each C represents a different part of how a diamond’s beauty and value is evaluated:

• Cut: How well a diamond’s facets interact with light (sparkle and brilliance)

• Color: The absence of color in a diamond (graded from D to Z)

• Clarity: The presence of natural inclusions or blemishes

• Carat Weight: The weight of a diamond (not to be confused with size)

Lab grown diamonds are graded using these exact same 4Cs standards as mined diamonds. Since lab created diamonds are physically, optically and chemically identical to their natural counterparts, independent gemological organizations officially grade their quality using the same rigorous parameters. The International Gemological Institute (IGI) notably set a precedent by being the first major diamond grading laboratory to give full 4Cs grading to lab grown diamonds and offer certificates that carry the same validity and reliability as those offered by GIA.

When buying loose diamonds or diamond jewelry, such as engagement rings, they generally accompanied by a complete grading report from GIA or IGI, which would provide verifiable details of the 4Cs, which are important for the assurance of the quality, for appraisals and for insurance. At Lucenjuri, most of our diamonds come with IGI certificates, ensuring they meet these globally recognized high standards.

Understanding how these four characteristics work independently and collectively is key to choosing the right diamond for your style, values, and budget.

Round

Oval

Cushion

Pear

Princess

Emerald

Marquise

Asscher

Radiant

Heart

Five lab diamonds of different shapes and sizes on a dark background

Diamond Cut

What Is Diamond Cut?

Diamond cut refers to how well a diamond’s facets interact with light. Unlike shape (round, oval, etc.), cut is about proportion, symmetry, and polish — all of which affect a diamond’s fire, brilliance, and scintillation. A masterfully cut diamond will reflect and refract light to create that sparkle we all know and love, even if it is smaller weight in carats.

Diamond Cut Grades Explained

The Gemological Institute of America (GIA) assigns cut grades ranging from Excellent to Poor for round brilliant diamonds. The grades assess factors like brightness, fire, scintillation, weight ratio, symmetry, and polish. At Lucenjuri, we prioritize Excellent and Very Good cuts to ensure your lab grown diamond captures the most light.

How Diamond Cut Affects Sparkle and Brilliance

Of the 4 Cs, cut is the most important when it comes to visual beauty. A poorly cut diamond may be highly graded for clarity and color but can still appear dull and unappealing. A well-cut diamond will have ideal proportions, precise angles, and the ability for light to bounce and refract from the facets for optimal brilliance.

Learn More About Diamond Cut

Gold ring with a large lab diamond and smaller diamonds on a light gray background

Diamond Color

What Is Diamond Color?

Diamond color measures the presence or absence of color in a white diamond. The less color, the higher the grade. The grades range from D (colorless) to Z (light yellow or brown). Most preferred diamonds are found at the lower end of the scale in the D to J category because they have white icy graded appearance.

Understanding the GIA Color Scale

• D–F: Colorless (premium range)

• G–J: Near colorless (excellent value with minimal warmth)

• K–M: Faint color (more visible yellowish tone)

The scale reflects subtle differences that can impact price, especially in larger carat sizes or certain shapes.

Lab Grown Diamonds vs Mined: Color Differences

Lab grown diamonds are chemically the same as mined diamonds, and they’re often produced with fewer impurities, resulting in higher color consistency. Lucenjuri diamonds are selected for exceptional color, often being colorless to near colorless for timeless elegance.

Learn More About Diamond Color

Two marquise-shaped lab diamonds held by tweezers on a gray background

Diamond Clarity

What Is Diamond Clarity?

Clarity of a diamond refers to inclusions (internal flaws) and blemishes (external marks). Most inclusions are microscopic and only visibed with magnification, but each inclusion can impact the appearance and value of a diamond based on number, size, and location.

Types of Inclusions and Blemishes

Common inclusions include:

• Feathers (internal fractures)

• Clouds (clusters of pinpoints)

• Crystals (internal mineral formations)

Surface blemishes may include:

• Scratches

• Polish lines

• Nicks

At Lucenjuri, we only offer diamonds graded SI2 and above, meaning all inclusions are eye-clean and do not impact sparkle.

How Clarity Affects Beauty and Value

Higher clarity grades (like VVS or VS) command premium prices but may not be visually different from SI1 or SI2 to the naked eye. Similarly, clarity matters most when the inclusion not only blocks brilliance but is also in the middle of the stone.

Learn More About Diamond Clarity

Lab diamond size chart with measurements in carats and millimeters, using a pencil for scale.

Diamond Carat

What Is a Carat?

A carat is unit of weight which is equivalent to 0.2 grams, that is used for measuring diamonds and gemstones. Carats are not a size measurement; you may have two diamonds which both weigh the same carat weight, but due to cut and shape they may appear to be different sizes.

Carat vs Size – What’s the Difference?

Carat weight is a measurement of mass, size is a visual appearance of what your are looking at. A 1 carat round diamond has an approximate measuring dimension of 6.5mm, and had you elongated the shape or cut it into a pear shape it may appear larger with the same total carat weight. Shallow cut stones or deep cut stones can also affect how big a diamond will visually appear.

Carat Weight and Diamond Price

As carat weight increases so do diamond prices — but not linearly. A 2 carat diamond is not going to cost twice the price of a 1 carat diamond, it may be 3x or upwards. That’s because larger diamonds are rarer, even lab grown diamonds are not immune to this rule of rarity and price growth. As a general rule and good strategy, try opting just below what we call the “magic numbers” like 0.90ct or 1.90ct, this will often offer better value.

Learn More About Diamond Carat

The Interplay of the 4Cs: Finding Your Perfect Balance

Why the 4 Cs Matter When Choosing a Diamond

The 4 Cs - cut, color, clarity, and carat - are the standardized ways to measure the quality and value of a diamond. Each "C" measures and adds its own element: cut adds the sparkle, color provides purity, clarity indicates cleanliness, and carat says something about presence. All of these are important aspects in defining both the beauty and cost for your diamond.

Understanding how each of these elements affects the look and value of your diamond helps you make an informed decision — a decision that fits your style, your budget and your values.

How the 4Cs Work Together

The magic happens in how the 4 Cs combine. For example:

• A slightly lower carat weight with an excellent cut will actually look larger and brighter than a heavier diamond with poor cut quality.

• A near-colorless diamond, say G color, can appear just as white as a D, especially when set in yellow gold, saving you hundreds.

• A diamond with a few tiny inclusions (SI1 clarity) can still be perfectly eye-clean and just as brilliant as a VS1 stone — at a better value.

The more that you understand how these characteristics work together, the more you can prioritize what's most important to you and still get a diamond that dazzles.

Do Lab Grown Diamonds Use the Same 4Cs as Mined Diamonds?

Absolutely! Lab diamonds are graded using the same grading standards as mined diamonds when it comes to the 4 Cs. Lab diamonds are certified by independent gemological labs like the IGI or GIA, with each lab using the same tools, measurements, and criteria.

Just like mined diamonds, lab grown diamonds are evaluated on:

• Cut: How well the diamond is shaped and polished

• Color: The lack of color (i.e., colorlessness)

• Clarity: The number and type of inclusions present

• Carat: The weight of the diamond

The only difference? Lab grown diamonds are created using advanced technology rather than mined from the earth — which means you can get higher quality at a better value, all while supporting a more ethical and sustainable choice.

Four Cs of Diamonds FAQs

Which of the 4 Cs is most important in diamonds?

While all four Cs — cut, color, clarity, and carat — matter, cut is widely considered the most important. A well-cut diamond will reflect more light and appear more brilliant, even if the other factors are slightly lower. By focusing on cut quality, the diamond you select will sparkle with the most fire and brilliancy.

What is the best combination of the 4 Cs of diamonds?

The ideal combination depends on your budget and preferences. For a well-balanced diamond:

• Prioritize an Excellent or Ideal cut.

• Choose G–H color for near-colorless beauty.

• Opt for VS2–SI1 clarity for eye-clean stones at better value.

• Select a carat weight that suits your style and finger size.

Lab grown diamonds offer the flexibility to get higher grades in each category without breaking your budget, so you can sparkle more for less!

Does diamond carat refer to its size?

Not exactly. Carat is the measure of a diamond's weight, not its size. One carat is equal to 0.2 grams. However, the visible size of a diamond also depends on its shape and cut proportions. also depend on the shape and the proportions of the cut. For example, an oval or pear-shaped diamond will often look larger than a round diamond that weighs the same.

What is a lab grown diamond?

A lab grown diamond is a real diamond that is made in a controlled environment. They are created using advanced technology and contain the same chemical, physical, and optical properties as a mined diamond. Lab diamonds differ from mined diamonds with respect to the origin of each type: lab diamonds are more ethical, sustainable, and affordable than mined diamonds, which make them a modern, viable alternative to mined stones.

Are lab grown diamonds graded by the same 4Cs standards as mined diamonds?

Yes. Lab grown diamonds are graded by independent gemological labs such as the IGI or GIA in the same way and to the same Four Cs criteria as mined diamonds. This provides assurances that cut, color, clarity, and carat for each diamond is graded in a consistent and objective way.

How do the 4Cs collectively impact a diamond's price?

Each of the 4 Cs plays a role in a diamond’s value:

• Carat and cut usually have the most impact on price.

• Color and clarity affect price less when staying within near-colorless and eye-clean ranges.

Together, the 4 Cs determine rarity, beauty, and market value. Even small upgrades in one category can significantly affect price — especially around “magic” carat sizes (like 1.0, 1.5, 2.0 carats).

How hard are diamonds?

Diamonds are the hardest natural substance on Earth, ranking 10 on the Mohs hardness scale. They are extremely scratch resistant - making them perfect for daily wear in an engagement ring. There is no difference between lab grown diamonds and mined diamonds in this regard.

What are the diamond grades?

Diamond grades refer to the individual ratings assigned to each of the 4 Cs:

• Cut: Excellent, Very Good, Good, Fair, Poor

• Color: D (colorless) to Z (light yellow or brown)

• Clarity: FL (Flawless) to I3 (Included)

• Carat: Measured to the hundredth (e.g., 1.25ct)

These grades help consumers understand a diamond’s quality and price — and are listed on official grading reports from labs like IGI and GIA.

How do diamond testers work?

Diamond testers are instruments that gauge a gemstone's ability to conduct heat or electricity. Real diamonds, whether lab grown or mined, both possess substantial thermal conductivity, that makes it easier for testers to identify them correctly.

What makes a diamond sparkle?

A diamond's sparkle is a result of its cut quality - the way light enters, bounces off and exits the stone. Diamonds with well cut stone dimensions and facet array create proportions that produce brilliance (white light), fire (colored light) and scintillation (sparkle when the diamond is moved). Out of all the Cs, the cut has the biggest impact on sparkle.

4Cs of Diamonds: Complete Guide