Diamond Grades
In purchasing your diamond you need to have some knowledge of the ‘4 C’s’ this is the manner in which all cut diamonds are graded and ultimately priced. Whilst the concept is simple on paper, it becomes much more difficult in practical application unless you have a vast array of equipment and experience in Diamond Grading, which is why your best ally when purchasing your diamond is a jeweller who is both trained in understanding how diamonds are graded, and trustworthy.

You also need to understand that perfection on paper is not always a sign of a fantastic looking stone. This is the reason we recommend that where possible, you view comparable stones side by side. It is the diamond, not the paper that will be viewed day in and day out!

The 4 C’s Concept

Carat
Carat refers to the physical weight of the diamond. Today the weight of 1 carat has been standardized at 1/5th gm or 0.2gms.
A ‘Carat’ is then sub-divided into ‘points’ of which 100 points = 1 Carat.
Therefore a half carat diamond - 0.50 carats (cts) = 50 points (pts).

Does size matter? Well that is very subjective, however you should remember that it is the combined criteria of all the 4 C’s - carat, clarity, colour and cut - that determines the cost of the stone. Depending on your budget, there will always be a larger stone available, although of lower quality, as opposed to a smaller stone of finer quality.

A larger diamond given all other qualities are the same will cost more per carat than one of a smaller size as the larger stone will be rarer.

Clarity
Almost all diamonds have small natural inclusions. Like humans, the perfect specimen is almost impossible to find! The inclusions can range from tiny crystals of diamonds or other minerals, to small feathers (miniscule fractures) within the stone. Remember, these are nature's inclusions and produce an individual fingerprint for each stone.

In some cases these inclusions are large enough to be visible to the naked eye and normally graded as Pique (P) or Included (I).
The most sought after diamonds range from SI (slightly included) through VS (very slightly included) and VVS (very, very slightly included) to LC (loupe clean) or FL (flawless).

The higher the grade, the rarer the stone even if all other qualities are the same. If combined with a good ‘cut’, the lack of inclusions enables the light to move cleanly through the stone without interference, which increases the ‘fire’ (sparkle).

Cut
Cut refers to both the shape and proportion of a diamond. Whilst diamonds are cut in a wide variety of shapes, the round brilliant cut is still the top choice.

There are international standards of cutting to produce the optimum of brilliance of a diamond. In 1919, Marcel Tolkowsky developed the mathematical proportions required to ensure the maximum dispersion of light from a round diamond, his design became the premier standard for the modern brilliant cut of today.

Sometimes, diamonds are cut for maximum size, which often results in a deviation from "good proportions". In grading the ‘Cut' of a diamond, a Grader or Valuer is looking at how this has affected the beauty of the diamond. It is estimated that only 5% of diamonds are cut to ‘ideal’ proportions.

Whilst the Colour & Clarity of a diamond has a great impact on the value of a stone, no less importance should be placed on the ‘cut’. When purchasing a diamond, note the price ranges for the same size and quality of stone, i.e. if the diamond is a 1ct round brilliant cut, F, Vs1. Why is there such a diversity in price? This will be due to the cut of the stone. Your Jeweller will be able to assist in talking you through this very fascinating feature.

Colour
This is actually a misnomer. White diamonds are actually graded for their ‘lack’ of colour. The majority of diamonds classed as ‘white’ have some secondary colouring - usually a yellowish tinge.  The purest colour grade is ‘D’, which represents a diamond that is completely pure and devoid of secondary colouring. To the other end of the scale, ‘L’ is the grade that represents a diamond that shows up the secondary colour quite readily in most forms of light.

Since the promotion of the 4 C’s the finer colours are in high demand, yet their rarity means much higher premiums to purchase.

Only white?
No, Diamonds come in a variety of rainbow colours from fancy canary yellows to blues, greens, pinks and reds as well as the large variety of champagnes and cognacs exhibiting ranges of soft lemons through to rich burnt orange/browns and chocolates. Some of these colours are so rare in nature such as the pinks and reds, that the prices can be prohibitive to most, with the exception of those with very healthy bank balances!! However be aware that these days many diamonds are ‘enhanced’, that is they are irradiated to produce a particular colour. An important reason to ensure that you know what you are buying. Your jeweller who has gemmological training and knowledge, is the best person to discuss this with.