Eight Essential Criteria for Choosing a Diamond Ring

Spring has sprung and the proposal and wedding season is upon us. Lovely ladies are being whisked away to glamorous and romantic destinations and asked a question short on syllables but big on impact: will you marry me?

Marriage and diamonds are an eternal pairing, this most precious of gemstone symbolising the engagement, the wedding, and anniversaries to follow. When it comes to finding the diamond ring of your dreams, however, there is such a dazzling array choice, how do you know where to start?

All to often do we rely on the commonly referenced ‘Four C’s’ to determine a diamond’s quality, therefore cost: carat, clarity, colour and cut (proportion). Although these criteria are crucial when influencing a purchasing decision, they must be considered in conjunction with four additional criteria that are, sadly, too often overlooked.


We’ve been speaking to diamond jewellery experts, Private Diamond Club, to learn more about the eight essential criteria for choosing a diamond ring:

Carat: The word most commonly associated with a diamond, referring to its weight. One carat equals 0.2 grams; therefore one gram equals 5 carats. The higher the carat of the diamond, the more expensive it is. But be aware: two diamonds of one carat each will have a lesser value than one diamond of two carats alone.

Clarity: Clarity refers to the internal characteristics of a diamond, called inclusions, natural occurrences that arise during the diamonds creation. The size, position, brightness and number of these inclusions determine the clarity of each diamond and they are graded from pure to heavily included, on a scale from LC (no trace of inclusions, the best) to lower quality P3 (big inclusions).

Colour: The most highly sought-after diamonds are colourless, with incredible reflective properties. Pure, colourless diamonds are graded D. At the other end of the scale, a grading of M-Z indicates a tinted colour to the stone, be it light yellow, brown, or grey.

Proportion (Cut): A well-cut diamond is easy to spot, as it will shimmer from all angles. The higher the grading of a diamond’s proportion (excellent the best, followed by very good), the superior the cut. Prices drop significantly for diamonds of a lower proportion.

Along with these Four C’s, it is essential to consider:

Shape: Diamonds come in a variety of shapes, which can greatly influence the overall look of the final jewellery setting. A round, or brilliant, cut is the most popular as it has the most reflective qualities. Other shapes include the classic princess cut, cushion, oval, heart, and marquise.

Symmetry:  The symmetry takes into account the facets (the flat, polished surface) of a diamond and the angles formed between them. The greater the balance between the angles of the facets, the more brightness a diamond will have. Symmetry is graded from excellent through to poor. The lower the symmetry, the lesser the value of the diamond.

Finish: Diamonds with a finish rated excellent or very good have no imperfections resulting from their size, no traces of the uncut diamond on the facets and no obstacles blocking the path of the light.

Fluorescence: Glowsticks are made for glowing in the dark, diamonds aren’t! Fluorescence, as separate to reflection, is considered a fault in a diamond. Rarer diamonds are graded nil or faint for their fluorescence. At the other end of the spectrum, the value of very strong and strong graded diamonds falls between 10% to 30%.

diamond ring


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