The Four C’s of Diamond Jewellery

The Four C’s of Diamond Jewellery

In order to determine the value and quality of a diamond, the Four C’s is widely used in the diamond jewellery business to evaluate each diamond. It was the GIA (Gemological Institute of America) that introduced the development of the International Diamond Grading System and the worldwide famous 4C’s principle to determine the value of gemstones namely:

 

Colour

This is one of the key factors considered when evaluating the value of a diamond and is therefore a very important characteristic (Click image to learn more)

 

Clarity

The number of imperfections under examination determines the clarity of the gemstone. (Click image to learn more)

 

Cut

The cut (also known as the “make” of a stone) is perhaps one of the most important factors to consider within the 4C’s grading system. (Click image to learn more)

 

Carat

The carat is the measurement of weight and not the size of the gemstone. The size of the diamond is determined by the grade of the cut. (Click image to learn more)

 

Colour

This is one of the key factors considered when evaluating the value of a diamond and is therefore a very important characteristic. Any diamond stone that is found to be colourless is graded as a “D” desending to a grade “Z” which is light yellow in colour. The GIA determines the colour grading of a diamond by comparing it to a master set in tightly controlled viewing and lighting conditions. Other major laboratories within the diamond trade use the same principle namely:

 

IGL – International Gemmological Institute
AGS – American Gemmological Society
HRD Antwerp – Institute of Gemmology

It can be said the less the colour in a gemstone, the higher the price (unless you are specifically buying a fancy coloured stone) and stones that are as clear as colourless water are those that are high in value within a grade rating of D – F with grade D being the most expensive. As the grading starts to descend towards Z you will find more colour is present in the gemstone. Above is the GIA colour grading scale that is widely used across the world.

 

Clarity

The number of imperfections under examination determines the clarity of the gemstone. Inclusions which are internal objects and blemishes namely external marks are closely examined and assessed using a 10x magnification. Within the GIA scaling system there is a total of 11 clarity grades ranging from flawless to imperfect.

 

The most valuable diamonds are those that have no imperfections namely with the GIA clarity grading code of FL (Flawless) being the most expensive followed by IF (internally flawless) to purchase. Below explains the GIA Clarity grading scale in detail.

 

 

 

FL (flawless) Within this gemstone no inclusion or blemishes of any kind are identified by a skilled grader using 10x magnification.
IF (internally flawless) Within this grade no inclusions but only minor surface blemishes are identified by a skilled grader using 10x magnification.
VVS1 and VVS2 (very,very slightly included) Within this grading inclusions are very difficult for a skilled grader to see using 10x magnification.
VS1 and VS2 (very slightly included) Within this grading the inclusions are clearly visible using 10x magnification but are identified as minor inclusions.
SI1 and SI2 (slightly included) Within this grading the inclusions can be easily identified by a skilled grader using 10x magnification but not normally visible by the naked eye.
11, I2 and I3 (included) Within this grading the inclusions are easily identified by a skilled grader using 10x magnification as well as the naked eye. We therefore do not recommend that you purchase diamonds of these grades.

 

It is our general recommendation that when choosing to purchase a diamond, we advise our customers to buy diamonds with a clarity of minimum SI2 or higher.

Cut

The cut (also known as the “make” of a stone) is perhaps one of the most important factors to consider within the 4C’s grading system. It determines how a diamond is cut to its finish and proportions taking into account the angle of the facets, the stones depth and the size of the table facet.

 

A diamond which has a perfect cut will ensure the light gets reflected and retracted all the way back up through the stone to give the colours of the spectrum and give a sparkle or flash of light during movement of the diamond stone.

 

 

The GIA developed a cut grading system as follows:

Excellent This is the most popular cut of its kind as it reflects almost every part of the light that enters the diamond giving the diamond stone fantastic brilliance and sparkle.
Very good This type of cut does not reflect as much light as the excellent cut but however only loses a small margin of light thus the stone giving a dispersion of light into the colours of the spectrum (fire).
Good This type of cut reflects most of the light that goes through but not as much of that of a very good cut. The diamond is exceptionally well priced and a lot cheaper to purchase than the very good and excellent cuts. This stone will still sparkle but there is noticeable difference when compared to both the very good and excellent cut.
Fair In this type of cut the light enters the diamond but a good proportion of it is lost through the sides and bottom of the diamond hence in return giving a reduction in what is seen in brilliance and fire. This particular cut is best used in diamonds that are less than 0.75ct where the difference in the sparkle is more difficult to detect.
Poor In this particular cut you will find a good majority of the light will not be reflected from the diamond as these stones are normally quite shallow and deep in order for the light to be reflected back out from the diamond.

The Quality of the cut determines how well the diamond will look and hence makes it one of the most important characteristics of the diamond.

 

The carat is the measurement of weight and not the size of the gemstone. The size of the diamond is determined by the grade of the cut. Carats are often referred to points and in simple terms a one carat diamond (1ct) weighs two hundred milligrams (one fifth of a gram) and is divided into one hundred points, so a diamond for example which has 50 points is often described as being half a carat or 0.50ct in weight. Small diamonds that are usually used in the shoulders of the ring are also referred to as points with one point for example being the same as 0.01carat.
Further examples can be seen below:

 

- 0.005ct is half a point
- 0.05ct is five points

- 0.25ct is twenty five points

- 0.50ct is fifty points

- 1.0ct is one hundred points

- 1.25ct is one hundred and twenty five points

- 1.50ct is one hundred and fifty points

 

The weight of the stone also determines the price of the stone but it must be remembered that two stones with exactly the same weight in carat might have a different price when comparing one against the other as the price is dependant on the other 4C characteristics being the cut, colour and clarity.

 

Within the diamond mining industry larger diamonds are very rare to find than smaller diamonds. Therefore you will always find larger diamonds have a greater value per carat hence the reason for the increase in price. A good example of this is that a two carat diamond will always be more expensive when compared to two one carat diamonds.

 

 

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