Carat is the unit of measurement used to weigh diamonds. One carat is the equivalent of 200 milligrams, or 0.2 grams. The word carat is derived from carob seeds that owing to their very slight weight-variance, were used to balance scales in ancient times.
Due to the processes involved in the formation of nature, large diamonds are created less frequently then smaller sized diamonds. Due to the rarity of larger sized diamonds they command substantially higher prices than smaller sized diamonds. For instance, a one carat diamond will cost more than two half carat diamonds of equal colour, clarity and cut.
However the weight of a diamond is but one of the factors used to value a diamond, and it should be understood that two diamonds of equal weight may have very different values, depending on their cut, clarity and colour. In fact, a smaller but perfectly cut diamond of whiter colour and flawless or nearflawless clarity can be more valuable than a larger diamond with a weaker shade of white and less clarity.
What to consider when deciding on diamond size:
It can often be difficult to choose between the size and the other criteria of a diamond but by considering the following factors your decision may be made easier:
Personal preference – do you or your loved one prefer to wear larger pieces of jewellery?
Finger size – slender fingers can make diamonds appear larger than their actual size;
Physical activity – a person who is very physically active will more likely knock or bump their ring;
As a product of nature diamonds may bear traces of the pressure and processes involved in their formation. These traces may appear on the diamond either externally, or internally and are referred to as "inclusions".
Where appearing internally on the diamond these inclusions may include air bubbles, cracks and non-diamond mineral deposits. Inclusions appearing externally may include scratches, pits and chips.
Not all diamonds have inclusions, and those without, are rare and often the most expensive. Diamonds with inclusions are graded according to the amount of inclusions detected.
Diamonds are graded for clarity under 10x magnification. Grading is allocated to a range of diamonds from "Flawless" to "Included-3" according to the following the following grades:
IF ( Flawless) :
No internal or external flaws;
IF (Internally Flawless) or LC (Loupe Clean):
No internal flaws but some surface flaws;
VVS1-VVS2 (Very Very Slightly Included):
Tiny inclusions which are very difficult to detect under 10x magnification;
VS1-VS2 (Very Slightly Included):
Tiny inclusions which are difficult to detect under 10x magnification;
SI1-SI2 (Slightly Included):
Tiny inclusions which are detectable under 10x magnification;
I1-I3 (Included):
These inclusions are detectable under 10x magnification, and are also visible to the human eye.
Each diamond's inclusions are unique to that diamond, with no two diamonds displaying the exact same inclusions. The Gemological Institute of America (GIA) diamond grading reports include graphic illustrations of inclusions found in diamonds. These graphic illustrations match the inclusions actually found in the diamonds, providing each diamond with its own "diamond fingerprint".
What to consider when deciding on your diamond's clarity:
While certainly setting the ultimate standard in an ideal diamond, flawless diamonds are not alone in providing exquisite diamonds.Generally, all of the grades, excluding the "I" grade, will be more an indication of a diamond's value than its unmagnified appearance. In other words, despite differences in grading, these diamonds will display few outward differences.
We suggest you choose a diamond that is "eye-clean" – not visible to the naked eye. "Eye-clean" diamonds are those in IF – SI2 clarity grading ranges.
Some brief details about these diamonds may assist you in making your decision:
VVS and VS graded diamonds are more expensive but are excellently valued, with difficult to detect inclusions;
SI1 and SI2 graded diamonds are more affordable with inclusions that remain almost invisible to the naked eye;
While diamonds can be found in almost every colour of the rainbow, colourless diamonds remain the most popular.
When describing the colour of a diamond reference is being made to the degree of colour found in that diamond. The less colour displayed in a diamond the better the colour grade. The notable exception to this would be in the case of fancy coloured diamonds, such as pink, yellow, green and blue. In fancy coloured diamonds a strong presence of colour would improve the diamond’s colour grading.
Diamonds displaying little colour will allow more light to pass though, creating a prism effect, with its spectrum of colours and flash, known as fire.
Diamonds are allocated a grade according to the level of colour they possess. This grading is alphabetical, starting with a D grade given to colourless diamonds and further movement down the alphabet for diamonds with progressively larger amounts of colour, ending in a Z+ grade.
The colour grades can be described as follows:
D, E & F grades:
These are clolourless diamonds. Only experienced diamond graders are capable of differentiating between D & E colours, and then only if these diamonds are unmounted. Diamond graders can more consistently identify F colour diamonds.
G, H, I & J grades:
These are near clourless diamonds, and very often appear colourless when mounted and graded face up. Non- diamond graders will not be able to detect colour in these diamonds. The average consumer will only be able to detect a subtle presence of colour around the J grade.
K, L & M grades:
Most consumers will be able to identify color in these diamonds, when mounted. However when these diamonds weigh less then half a carat and are mounted in white metal, they may still appear as clourless.
O –Z grades:
Most consumers will be quick to notice colour in these diamonds, regardless of how the diamond is mounted. These diamonds will range between a very-light yellow and a light yellow, however brown and grey tones may also be identified.
What to consider when deciding on your diamond’s colour:>
Where your setting is in yellow gold you may be able to chose a lower colour grade than if you were choosing a platinum or white gold setting;
Yellow shades, found in K-M graded diamonds, may draw out the latent character of a jewellery piece, depending on the piece selected.
A word on fluorescence
Fluorescence is the reaction of some diamonds to exposure of UV lighting. Generally it has been understood that fluorescence makes clear diamonds appear as cloudy and yellow tinted diamonds appear as clear when subject to UV lighting. Under normal lighting conditions fluorescence is not detectable.
However, the presence or absence of fluorescence has had only minor importance in the purchasing decisions of most diamond buyers. This is because of the following:
Fluorescence is only detectable under UV lighting ;
Under UV lighting even trained gemologists are unable to consistently agree on the effects of fluorescence and;
Some buyers prefer the aesthetic effect of fluorescence.
Our suggestion is that buyers who are able to purchase colourless or near-colourless diamonds at reduced prices because of the presence of fluorescence, should seriously consider this option.
