The 4c's a brief overview
The most important of the 4c's because of its influence over the sparkle and play of light in the diamond. The cut is also the only of the 4c's that human hand plays any roll in.
ColourThe second most important of the 4c's is colour, which refers to a diamond's lack of colour. The less colour, the higher the grade. The cut grades start at D through to Z.
Often considered the least important of the 4c's because the tiny imperfections (inclusions and blemishes) are often only visible under 10 x magnification.
The term carat refers to the diamond's total weight and not its size in mm.
A more in-depth look at the 4c's
The diamond cut is the most important factor to consider when buying a diamond. The cut is graded by the degree of precision that each of the facets have been placed on the diamond: the angles and proportions. This is necessary to create maximum sparkle, fire, brilliance and scintillation. A diamond without a high cut grade even a diamond of high quality can appear dull and lifeless. A diamond cut poorly and too deep can face-up smaller than it actually is. This is why it is so important especially when choosing a round brilliant diamond.
Brilliance: the amount of light reflected back out of your diamond
Fire: the dispersion of light into the seven colours of the spectrum: red, orange, yellow, green, blue, indigo, and violet
Scintillation: the flashes of light, or sparkle, you see in your diamond when you move it around
To achieve maximum fire, brilliance and scintillation, each facet must be in perfect alignment. A diamond internally reflects light from one mirror-like facet to another, then disperses and reflects the light back through the top of the diamond. The cut grade will be higher when more of the facets line up edge to edge, angle to angle and lower when they don’t. Lower cut grade = less light = less sparkle. This is why the quality of the cut can visually be determined by the amount of the brilliance, fire and scintillation present in your diamond. It's also why some diamonds just look better and sparkle more than others.
This is the GIA grading
* Buying tip We recommend buying a diamond with a cut grade of at least very good and above. This is where you should spend your money, because you can actually see the difference. Remember, you're not wearing the paper work around on your finger.
This is the second most important characteristic to consider when choosing a diamond. It's the lack of colour (tint) in the diamond that makes the diamond more rare and therefore more expensive.
The Gemological Institute of America (GIA) grades diamond colour on a scale of D (colourless) to Z (light yellow or brown). D-Z diamonds are also known as white diamonds, even though most diamonds, including H colour diamonds and G colour diamonds, have varying amounts of colour.
The colour of a diamond is graded by the GIA in colour range groups from colourless to light in colour, you can see this on the chart below. Diamonds graded D have the most lack of colour and are very rare, whereas G and H colour diamonds are near colourless,. This means that they are priced lower which makes them excellent value diamonds. The further you move down the colour chart, the lower the colour grade is, and the more noticeable the light yellow hue becomes and the less rare they are.
* Buying tips The brilliance is the first thing you notice about a diamond, colour is the second. Getting these two factors right are important. If you're looking for best value, choose G-J diamond colour grades these are in the near colourless category. It's very hard to see the colour in these colour grades with the naked eye, but the savings can be significant. It's important to also note here that the colour of the setting can affect how the colour of the diamond looks. For example if you're opting for a white metal like Platinum or white gold then you would go for G-H or higher, however if you are setting in yellow or rose golds I-J would be fine as the diamond can take on some of the tint of the metal.
Diamond clarity is dictated by the amount of small imperfections found on the surface and internally within the diamond. The flaws on the surface are called blemishes, and when found internally these are known as inclusions. These tiny, natural blemishes and inclusions are visible under 10 x magnification and do not affect a diamond’s beauty in any way. diamonds with the least and smallest inclusions receive the highest clarity grades.
Clarity is the least important factor of the 4c's. The reason being is that most diamonds have blemishes and small inclusions and they are so small, microscopic in fact that they are unable to be seen with an untrained or unaided eye.
* Buying tips To get best value, select a diamond with inclusions that can’t be seen through the crown ( the top of the diamond) without magnification, we call eye-clean. Diamonds that fall into this category are Slightly included (SI) or Very slightly included (VS) clarity grade. These diamonds will be much less expensive than the extremely rare Flawless (FL) or Internally Flawless (IF) diamonds.
Diamond carat is often misunderstood and refers to a diamond's weight, not its size in dimensions. This mean that you can have two diamonds with identically carat weight but they may not measure the same in mm especially if they are cut too deep, so they won't sparkle and will look so much smaller.
* Buying tips Buy shy to maximise your budget - which means opt for a carat weight that's slightly below the whole and half carat marks. For example, instead of a 1.00ct diamond, consider buying a 0.90ct. This will save you money and the slight size difference will never be noticed.