The 4Cs of Diamonds: Cut, Colour, Clarity & Carat Explained

When shopping for a diamond—whether lab grown or mined—understanding the 4Cs is essential. Developed by the Gemological Institute of America (GIA), the 4Cs are the universal language used to assess a diamond’s quality and value.

In this guide, we’ll explore each “C” in detail, explain how they work together, and help you make informed choices when selecting a diamond—whether it’s for an engagement ring, pendant, or custom heirloom.

What Are the 4Cs?

The 4Cs stand for:

1. Cut

2. Colour

3. Clarity

4. Carat weight

These factors are assessed by grading laboratories like GIA or IGI, and combined they determine a diamond’s appearance, value, and light performance.

Understanding the 4Cs helps you prioritise what matters most based on your personal preferences, style, and budget.

1. Cut – The Key to Sparkle

Many people think carat size is most important—but cut is the factor that most affects a diamond’s brilliance and fire. Even a colourless, flawless diamond will look dull if it’s poorly cut.

What Cut Measures:

• Proportions – How each facet is angled and aligned

• Symmetry – Balance and evenness of shape

• Polish – Smoothness of the diamond's surface

• Light Performance – How the diamond reflects and refracts light

Cut Grades (Round Diamonds Only):

• Excellent

• Very Good

• Good

• Fair

• Poor

Other shapes (oval, pear, radiant, marquise) don’t receive a formal cut grade, but polish and symmetry are still evaluated—and proportions matter greatly.

💎 Experience clean-cut sparkle in the
👉 Elysian Oval Solitaire Ring

2. Colour – The Whiter, the Rarer

Diamond colour refers to how colourless a stone appears. The less colour, the higher the grade.

GIA Colour Scale:

• D–F: Colourless

• G–J: Near Colourless

• K–M: Faint tint

• N–Z: Noticeable yellow or brown hue

Most high-quality lab grown diamonds fall in the D–F range. Some clients prefer a warmer tone for vintage-style pieces or yellow gold settings.

Note:

Fancy coloured diamonds (pink, yellow, blue) are graded differently under a “Fancy Colour” system based on hue, tone, and saturation.

3. Clarity – Natural Inclusions

Clarity describes the presence or absence of inclusions and blemishes in a diamond. These internal or surface features form naturally (or during growth) and are common in nearly all diamonds.

Clarity Scale (from highest to lowest):

• FL – Flawless

• IF – Internally Flawless

• VVS1/VVS2 – Very, Very Slightly Included

• VS1/VS2 – Very Slightly Included

• SI1/SI2 – Slightly Included

• I1–I3 – Included (visible to the naked eye)

Most lab grown diamonds are VS1–VVS1, making them eye-clean with minimal or invisible inclusions.

Clarity becomes more important in larger stones or emerald cuts, where the flat facets reveal more.

4. Carat – Weight, Not Size

Carat refers to a diamond’s weight, not just its physical dimensions. A 1 carat diamond weighs 0.2 grams. Larger diamonds are rarer and often more expensive—but carat alone doesn’t determine appearance.

For example, a poorly cut 1.2ct diamond may appear smaller than a well-cut 1.0ct.

Cut, depth, and shape all influence how large the diamond appears “face-up” on the finger.

How the 4Cs Work Together

The 4Cs are not independent—they work as a system.

For example:

• A lower carat weight with an excellent cut may look larger than a higher carat diamond with poor cut.

• A VS2 clarity diamond can appear flawless if the inclusions are tiny and well placed.

• A G colour may look just as white as a D colour—especially in yellow or rose gold settings.

At Diamond Lab, we help clients balance the 4Cs based on personal preferences, style, and budget—whether that means going big on carat or prioritising cut and clarity.

Lab Grown Diamonds & the 4Cs

Lab grown diamonds are graded using the same criteria as mined diamonds. GIA and IGI grade lab diamonds with equal rigour and transparency.

Benefits of lab grown diamonds:

• Often higher clarity and colour due to controlled growth

• Better value per carat

• Full 4C transparency and certification

• Conflict-free and sustainable sourcing

Final Thoughts: Know Before You Buy

Understanding the 4Cs empowers you to choose a diamond that aligns with what matters most—whether that’s sparkle, size, budget, or brilliance. Don’t just buy by carat weight or price tag—know what you’re getting, and make your diamond purchase a truly informed one.

Need Help Choosing? Let’s Talk

Whether you're just starting out or comparing certified stones, we’ll guide you through each C with clarity. Book a one-on-one consultation with our expert team in Perth or online.

📍 Contact us today and let’s create something timeless together.