Of the 4 C’s, Cut is the most important criteria. It determines how sparkling and brilliant a diamond is.
A well cut diamond display these three characteristic, Brightness (the amount of light reflected from the diamond), Fire (the dispersion of light into rainbow colours as it passes through the diamond) and scintillation (the flashes of light as you move the diamond, commonly known as “Bling”)
A well cut diamond gives you the maximum return of light as light strikes the diamond. It will sparkle no matter how big or small the diamond, and regardless of its Colour.
A poorly cut diamond however, may be either too shallow or deep. These cuts of diamonds are cheaper than a well cut one, but it will not be as sparkling, as light leaks out from the side of the diamond, which makes the diamond dull and lifeless.
Diamonds are graded by how colourless they are. The lesser the Colour a diamonds has, the more valuable it is. Most diamonds have a little tinge of yellow, while only small percentages are colourless or near colourless.
D to F Colour diamonds is colourless and they are known as Collection colours. They are rare and highly desirable.
While G to I Colour is near colourless, and it is widely used in most Jewellery. F
rom J Colour onwards to Z, a yellow tinge can be easily detected.
Before the colour grading was universalized by GIA, starting from D to Z colour, a variety of other colour grading systems were loosely used. From A, B, C to Arabic 0, 1, 2, 3, and even the terms, which can often be misinterpreted.
GIA wanted a fresh start with the Colour grading, without wanting to associate with earlier system. That is why they started the grading with the letter D. (Not because letter D stands for Diamond).
Natural diamonds are formed deep within the earth, and most have what we call Birthmarks; Inclusions (internal) and blemishes (external). Every diamond has its unique birthmarks, like fingerprints and no two diamonds are alike.
There are 5 factors to consider when giving the Clarity grading; the size of inclusion, the quantity, the position, nature and colour of the inclusion.
As diamonds are created deep within the earth, most of them would have unique identification birthmarks, known as inclusions (internal) or blemishes (external). Diamonds with no or few inclusions are rare, it in turn affects the price. These Clarity characteristics are microscopic in nature; even down to Clarity grading of SI1, most of these birthmarks are not visible to the naked eye, and they are not easy to spot even under a10x magnification to an untrain eye.
Carat is the measurement of the weight of diamond.
As a fraction of a carat can represent a considerable value in price, exact precision is important. In our profession, diamonds are weighed to a thousandth of a carat. So you get what you pay for, and nothing less.
To achieve an excellent cut diamond from a rough (the original state of diamond before it is cut and polished) up to 60% of diamond rough has to be sacrificed. This is why a well cut diamond is more valuable compared to a poorly cut diamond.
Some choose to sacrifice beauty in order not to waste so much of the precious diamond rough and the end result is an average cut diamond that does not sparkle as much.
The modern carat system started with the carob seed. Early traders used the small but uniform seeds as counterweights in the balance scales. The carat is the same weight in every part of the world.
To help you understand better, 1.00ct is equals to 0.2 grams.