The 4Cs of diamonds. Everything you need to know.
Cut. Colour. Clarity. Carat. These four characteristics determine the quality, appearance, and value of every diamond. Understanding them means choosing with confidence — not guesswork.
How a diamond is cut determines how it shines.
Of all the 4Cs, cut has the greatest impact on a diamond's beauty. It is the only characteristic that is entirely in the hands of the craftsman — not determined by nature. A diamond with excellent colour and clarity will still look dull if it is poorly cut.
Cut does not refer to the shape of the diamond — round, oval, cushion, pear. It refers to the precision of the facets: their angles, proportions, symmetry, and how they interact with light. When a diamond is cut well, light enters through the table, bounces off the internal facets, and returns to your eye as brilliance and fire.
A poorly cut diamond leaks light from the sides and bottom of the stone. It looks smaller, dimmer, and less alive — regardless of what its colour or clarity grades say on paper.
"A well-cut 1ct diamond will outshine a poorly cut 1.5ct stone. Cut is that powerful."
How much colour is in your diamond.
Diamond colour is graded on a scale from D to Z, where D is completely colourless and Z has a visible yellow or brown tint. The scale was established by the Gemological Institute of America and is used by all major grading laboratories, including IGI.
The difference between adjacent grades is extremely subtle — a trained gemologist examining a stone under controlled laboratory conditions can distinguish them, but most people cannot tell the difference between, say, an E and an F with the naked eye, particularly when a diamond is set in jewellery.
What this means practically: the jump in price between grades is often far more significant than the visible difference. G and H colour diamonds face up white to the naked eye in almost all settings and represent exceptional value compared to D–F stones.
What is inside — and on the surface of — your diamond.
Clarity refers to the presence of inclusions (internal characteristics) and blemishes (surface characteristics) within a diamond. Almost all diamonds contain some of these natural features — they form during the crystal growth process under extreme heat and pressure. In lab grown diamonds, they form during the same crystal growth process in the laboratory.
Inclusions are not flaws in the way a chip or crack would be. They are natural markers of a diamond's formation — unique to each stone, like a fingerprint. The question is only whether they are visible, and whether they affect the diamond's beauty or durability.
Most people are surprised to learn that the majority of inclusions are completely invisible to the naked eye. A VS1 diamond looks exactly as clean as a Flawless diamond when you are wearing it — the difference exists only under 10x magnification in a laboratory.
"Eye-clean is the standard that matters. Not Flawless."
Approximate diameter for round brilliant cut. Fancy shapes vary.
How much your diamond weighs.
Carat is the unit of weight used for diamonds. One carat equals 0.2 grams, and is divided into 100 points — so a 0.75 carat diamond is also described as a 75-point diamond. The word comes from the carob seed, historically used as a counterweight on precision scales.
It is important to understand that carat weight is not the same as physical size. A well-cut 0.90ct diamond can appear larger face-up than a poorly cut 1.10ct diamond, because the poorly cut stone carries more weight in its depth rather than its spread. This is one of the many reasons cut quality matters so much.
Carat weight also follows a price curve rather than a straight line. A 1.00ct diamond costs meaningfully more per carat than a 0.90ct diamond of the same quality — because whole-carat and half-carat milestones carry a price premium based on demand. A 0.95ct stone is technically almost identical in size but can be significantly more affordable.
How to balance the 4Cs for your budget.
No single C exists in isolation. The 4Cs interact — and understanding which to prioritise based on what you value most is the key to getting the best diamond for your investment.
Cut has the greatest visible impact of all four characteristics. Always choose the best cut grade you can afford before adjusting other factors. A stone with excellent cut but lower colour or clarity will almost always look more beautiful than the reverse.
Once cut is secured, look at colour — aiming for G or H for most settings. Then consider clarity: VS1 to SI1 is the practical sweet spot. Most people cannot see the difference between a VS1 and a Flawless diamond with the naked eye, but the price difference is significant.
Once your quality floor is set, use carat weight to find the size that fits your budget. Consider just-under weights (0.90ct vs 1.00ct) for significant savings. With lab grown diamonds, you can often achieve a meaningfully larger stone at the same investment as a smaller mined diamond.
Questions about the 4Cs.
The most common questions we hear from customers when they are choosing their diamond. If yours is not here — reach out on WhatsApp and we will answer it directly.
Ask on WhatsApp