Your Essential Guide To The 4 C’s When Buying a Diamond or Gemstone

When choosing a diamond or gemstone, it’s important to understand the Four Cs: Cut, Colour, Clarity, and Carat. These four characteristics are the global standard for evaluating diamond quality and value. Understanding the Four Cs will help you find the perfect balance between beauty, brilliance, and budget.

1. Cut – The Key to a Diamond’s Sparkle

Of all the Four Cs, cut has the greatest impact on how dazzling a diamond appears. A diamond’s cut determines how light enters and reflects within the stone, creating that signature sparkle. Even a diamond with perfect colour and clarity can look dull if the cut is poor.  A well cut diamond reflects light evenly across its surface, maximising brilliance. Cut grades range are Excellent, Very Good, Good and Poor. 

2. Colour – The Shade of Perfection

A diamond’s colour measures how clear or tinted the stone appears. The grading scale runs from D (colourless) to Z (light yellow or brown).Completely colourless diamonds (D–F) are the rarest and most valuable, offering a pure, icy brilliance. However, near-colourless diamonds (G–J) can provide exceptional beauty at a more affordable price, appearing white to the naked eye once set in jewellery. For those seeking something more distinctive, coloured diamonds, such as pink, yellow, or blue are chosen for their rarity and vibrant hues, making them stunning statement pieces.

3. Clarity – The Fingerprint of Nature

No two diamonds are alike, and clarity reveals their unique natural characteristics. Most diamonds contain tiny inclusions (internal marks) or blemishes (surface imperfections) formed during their creation. The clarity scale ranges from Flawless (FL) to Included (I1–I3). While flawless diamonds are incredibly rare, many inclusions are microscopic and invisible to the naked eye. A diamond with eye-clean clarity, where imperfections aren’t visible without magnification, offers excellent value and beauty.

4. Carat – The Weight Behind the Brilliance

Carat refers to a diamond’s weight, not its size. One carat equals 0.2 grams. Larger diamonds are rarer, which makes carat weight a key factor in price. Two diamonds of equal carat weight can look very different depending on their cut and proportions. When choosing your stone, it’s worthwhile considering if you should prioritise cut quality and overall sparkle over size alone. A slightly smaller, well-cut diamond will often appear more radiant than a heavier, poorly cut one.

Finding Your Perfect Diamond

The Four Cs of diamonds work together to define each stone’s beauty and value. The ideal combination depends on your personal preferences, whether that’s maximum brilliance, clarity, or size.

At Toulson Jones Jewellers, we specialise in helping you choose the perfect diamond.  Our experts can help with any questions you have and we have a vast selection in store to help guide you to select the perfect diamond or gemstone. Visit us in store to explore our stunning range and let our experts guide you with any assistance you require.