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Carat, Colour, Clarity and Cut; The Four Cs Explained

What makes a diamond special? Is it the cut? Or maybe it's the carat size? The colour and clarity?In fact, it's all of them. And all four factors, known as The Four C's, will help you see what makes a truly dazzling diamond. Here's a look at the criteria:


The carat refers to the weight of a diamond. As a diamond's weight increases, its value does also. For example, a 3-carat diamond is worth much more than three 1-carat diamonds - something to keep in mind when choosing among different ring designs.The word carat comes from a natural source: the seeds of a carob tree. Diamonds were traditionally weighed against these seeds until a more scientific and accurate method was employed.The unit of weight used for diamonds and other gemstones today is a metric carat, which is equal to 0.20 grams. Nearly 142 carat equals once ounce.


The colour of a diamond is a true differentiator. A truly colourless diamond is a rarity, but you'll find a wide range of beautiful stones that reflect a warm white to yellow shade. The best choice here is a matter of personal preference.

Most diamonds have at least a trace of yellow or brown body colour, however, the colour palette of a diamond is richly varied; diamonds can cover the entire spectrum of colours. Naturally coloured diamonds are rare and referred to as fancies. These diamonds can come in tints such as a green, intense yellow (canary), red, blue, pink, amber and even black. Because of their rarity, fancy colours are held in very high esteem, especially when there is intense colour saturation.

Aside from certain fancies, the most valuable diamonds on the market today are completely colourless stones. In this respect, the diamond is the only gemstone whose colourlessness renders it more valuable.

There are international standards which have been established to grade the value of a diamond based upon its colour.

At Michael Hill, we use the GIA (Gemological Institute of America) diamond grading system because it is the system most widely used and referred to by jewellers all over the world. On the GIA scale, diamond colour grades are indicated from colourless to yellow as D through Z. The top grade colour is called D.


The Clarity is also important. After a diamond is cut, its unique inner beauty shines through. Every diamond is different, and tiny, natural imperfections, arise during formation - the fewer the imperfections, the higher the value. Flawless diamonds are quite rare, and clarity defines the distinctive beauty of each stone.


The Cut or shape is chosen by a skilled artisan – they use their knowledge and expertise to unlock a diamond’s potential to shine. Our craftsmen delicately design the cut that will best transform a rough diamond into a sparkling stone. There are many cuts – including round brilliant, princess, and baguette – but what’s more important are proportions, symmetry, and polish. An accurately proportioned stone will attract a higher price, as the cut of a diamond dramatically influences its fire - the rainbow flashes of light reflected from within the stone, and its brilliance - its brightness.

The term cut is sometimes confusing because it has a variety of meanings. Generally, cut refers to:

  • The shape of a gemstone

  • The cutting style (such as brilliant or step cut)

  • The proportions of the stone (such as big or small table facet, deep or shallow pavilion)

  • The make is determined by the angles of the crown and pavilion facets, the size of the table and culet and the overall symmetry of the stone.

  • The finish of a stone (such as polishing marks or smooth flawless surface, misshapen or symmetrical facets).

After careful examination of the rough stone, the cutter decides on a final shape for the diamond. Their decision is influenced by several factors such as the original shape of the stone, its dimensions, inclusions and the inevitable loss of weight during cutting.

It is the cut that enables a diamond to make the best use of light. When a diamond is cut to good proportions, light is reflected from one facet to another and then dispersed through the top of the stone. If the cut of the diamond is too deep, some light escapes through the opposite side of the pavilion. If the cut is too shallow, light escapes through the pavilion before it can be reflected.

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