Diamond Grading – The Four Cs

Cut, Colour, Clarity, and Carat

Unlike buying clothes, shoes, or cars, buying a diamond is a very special experience. It represents the gesture of love, and faithfulness as well as signifies a milestone in people’s life. When shopping for diamonds, it is essential to know which shape suits your personal preference and how to evaluate the quality of a diamond.

The Four C’s method refers to cut, colour, clarity, and carat. It was introduced by GIA (The Gemological Institute of America) and is a global method used to assess the standard for describing diamonds. Let’s take a look to find out what characteristics you should consider when purchasing diamonds.

Cut

The cut of a diamond is what makes a diamond sparkle. A poorly cut diamond won’t have a good light return and can look lifeless no matter how high the colour and clarity are.

A diamond’s beauty can be affected by the skill of the cutter in achieving the correct combination of crown angles and depth percentages. If a diamond is cut well, a ray of light enters the table of a diamond and reflects on the internal mirrors, returning with a sparkle for all to see. This is a scientific principle known as ‘total internal reflection’.

The cut of a diamond has three attributes:

Brilliance (or light reflection)

Fire (or dispersion of light into the colours of the spectrum)

Scintillation (or sparkle).

The proportion of a diamond also plays a large role in how it interacts with light. A diamond cut too deep, or shallow won’t return light through the side it entered. It will lose it through the bottom or another side.

Colour

When it comes to colour, it’s all about what you can’t see. Diamonds that are colourless or near colourless are chemically pure. These are rarer which makes them more valuable.

Increasing degrees of colour is measured on a scale starting from D (colourless) to Z (deeply coloured). Diamond Boutique only use diamonds within the “colourless” and “near colourless” range and our minimum standard colour is ‘H’.

The colour also affects the diamond’s appearance. A diamond with a poor colour grade has a slight yellow tinge whereas a diamond with a high colour grade is a brilliant white.  

Clarity

The clarity of a diamond measures the purity and rarity based on the visibility of its characteristics. These characteristics are internal ‘inclusions’ or external ‘blemishes’ that can affect how light interacts with a diamond to give it its sparkle  

Clarity is ranked on a scale from IF to P3, where ‘IF’ is Flawless, and ‘P3’ is heavily included. This rank is calculated based on how many inclusions there are, how big they are, what their colouring is and where they’re located in the stone. Some may be visible to the naked eye (which would result in a low grade such as P1, P2 or P3), and others would need a loop or microscope to see. Diamond Boutique’s minimum standard for clarity is SI2.

Please note that the clarity characteristics are affected by other diamond qualities such as shape/cut and size. Some step cut diamonds such as emerald or baguette, have larger facets where imperfections can be more noticeable.

Carat

Carat (ct) refers to the unit of measurement when weighing diamonds and gemstones. One carat is equivalent to 0.2 grams and it is divided into 100 points. For example, jewellers may describe 1/4 carat (0.25ct) weight diamond as 25 points. However, stones that weigh greater than one carat will be expressed in carat and decimals.

A diamond’s carat can appear differently depending on the diamond shape.  Two diamonds of the same carat may appear different in size due to one being cut shallower than the other.

Diamond shape

Even though the diamond shape is not part of the Four C’s grading system, people can confuse it with the cut attribute. When shopping for a diamond, the shape is often the first factor that is considered by customers. Each shape is distinctive and has its own unique features.

There are many different factors to consider when selecting the perfect shape for you. The diamond grading system is based mostly on the brilliant cut. It is important to speak to a diamond specialist when selecting the correct combination of aspects for various shaped diamonds.

Diamond Jewellery Canberra

At Diamond Boutique we only work with diamonds that are of high quality. We have lab grown diamonds as well as natural diamonds. Whether you’re in the market for an engagement ring, dress ring, pendants, necklace, bracelet, or bangle featuring a brilliant diamond, we can help.

Contact us or drop in-store to shop from our range on display or talk to us about creating a custom-made piece.