Everything You Need to Know About Diamonds

Diamonds are the most celebrated gemstone in the world and one of the most misunderstood. Whether you are buying your first diamond or adding to a collection, understanding the basics transforms the experience from overwhelming to genuinely enjoyable.

How Diamonds Are Formed

Natural diamonds formed between one and three billion years ago, deep within the earth's mantle under extreme heat and pressure. They were carried to the surface by volcanic activity in formations called kimberlite pipes. What you hold in your hand when you hold a diamond is, quite literally, one of the oldest and hardest things on earth. Diamond is the hardest natural substance known a 10 on the Mohs scale which is part of what makes it so extraordinary as a stone for everyday jewellery.

The Four Cs

Every diamond is assessed on four criteria: cut, colour, clarity, and carat weight. Cut is the most important for beauty, it determines how well the diamond reflects and refracts light. A perfectly cut diamond will sparkle brilliantly even in low light; a poorly cut one will look flat and dull regardless of its size. Colour is graded from D (completely colourless) to Z (noticeably yellow or brown), with D through G appearing white to the naked eye. Clarity measures internal inclusions and surface blemishes, with grades from Flawless down to Included. Carat is simply weight - one carat equals 0.2 grams.

Why Cut Matters Most

Of the Four Cs, cut has the greatest impact on how a diamond looks. Two diamonds with identical colour and clarity grades will look completely different if one is well-cut and the other is not. When comparing diamonds, always prioritise cut quality. An excellent or ideal cut grade from a reputable grading laboratory is the most reliable indicator that a diamond will perform beautifully in real life.

Diamond Shapes

The round brilliant is the most popular diamond shape and is specifically engineered to maximise sparkle. Fancy shapes - princess, oval, cushion, emerald, pear, marquise, and others each have their own character and visual effect. Oval and elongated shapes tend to make a stone look larger than its carat weight suggests. Emerald and Asscher cuts show large open facets that emphasise clarity and colour rather than sparkle. The right shape depends entirely on personal preference and the setting style.

Understanding Certification

A certified diamond comes with a grading report from an independent laboratory. The GIA (Gemological Institute of America) and IGI (International Gemological Institute) are the most widely recognised. A certificate does not make a diamond more valuable, it simply verifies what the diamond already is. For any significant diamond purchase, certification provides important peace of mind and makes resale far more straightforward. Always ask to see the certificate and verify it matches the stone.