| Over the years, diamond professionals have developed standards
for comparing and evaluating these precious stones. These
standards are better known as the 4 C's: Colour, Clarity,
Cut, and Carat weight
Together the 4 C's affect the appearance and value of
the diamond. No other gemstone is judged so strictly. A diamond's
value is influenced by its rarity. Even the slightest differences
can make a huge difference in value.
Learn about the
colour range from D-Z and how it's colour that makes a diamond
sparkle.
Do you get more for your money when you buy
a flawless diamond? Cut Possibly the most overlooked of all
the C's - cut is the one property most directly influenced by
man.
See how a diamond's weight affects its value.
Colour is a decisive aspect when judging the beauty of a diamond.
The whiter and more colourless the diamond, the greater its
rarity and value. Generally speaking, it is the colour that
gives a diamond its sparkle.
The more colourless the diamond,
the more brilliantly it will sparkle. Diamonds are graded on
a colour scale, which was set-up, by the Gemmological Institute
of America (GIA).
This scale ranges from D (colourless) to Z. The price difference
between two adjacent colour grades can be significant. Many
diamonds may appear colourless to the untrained eye but on
closer inspection will almost certainly contain very slight
traces of brown, yellow or grey. Coloured diamonds are also
found and can include blues, pinks, greens, browns, oranges
and very rarely, reds.
It is the cut of a diamond, above all other properties that
will determine the stone's fire and brilliance. Through manipulation
of a stone's facets, a diamond cutter can enhance a diamond's
natural ability to reflect and refract light.
When light enters a well cut diamond, it is reflected from
one facet to another and then dispersed through the top of
the stone. Each facet acts as a light dispersing mirror and
it is this light that when reflected out of the stone, gives
a diamond its sparkle.
If the cut of the diamond is too deep, some light will escape
through the opposite sides of the pavillion and the stone
will be less radiant.
Likewise, if the cut is too shallow, some light will escape
through the pavillion before it can be reflected. See diagram
below
As well as referring to the quality of craftsmanship of a
diamond, cut also refers to a diamond's shape.
Diamonds can be cut in many different shapes and will all
handle light differently. The longer shapes tend to have a
slight 'bow tie' effect. This means they have a small zone
in the centre where light leaks out of the bottom of the stone.
This creates a darker area in the shape of a bow tie. This
is especially true for the Pear, Oval, Marquise, and Heart
shapes.
The Round Brilliant Ideal Cut will provide the maximum fire
and brilliance due to the positions and angles of its facets.
It will reflect the most light will therefore provide the
most sparkle.
Ideal cut diamonds command a slight premium due to a number
of reasons.
(1) the extra care and skill needed during cutting
(2) more of the rough is usually cut away
(3) they are scarce and in high demand.
The Round Brilliant Ideal Cut will provide the maximum fire
and brilliance due to the positions and angles of its facets.
It will reflect the most light will therefore provide the
most sparkle.
Ideal cut diamonds command a slight premium due to a number
of reasons:
(1) the extra care and skill needed during cutting
(2) more of the rough is usually cut away
(3) they are scarce and in high demand.
The different diamond shapes are shown below:
The weight of a diamond is expressed in 'carats'. One carat
is equivalent to 0.2 grams.
Within the trade, one carat is divided into one hundred units
called points; a stone weighing 0.64 carats would be referred
to as a '64 pointer'.
It is vitally important to take into account all four C's
when choosing your diamond. Larger doesn't necessarily mean
better. A large stone will not be very valuable if it is cut
badly or is of a low grade colour.
However, for a given quality of diamond, the price will rise
exponentially as the stone gets larger. For example, a 4 carat
stone is worth far more that double that of a 2 carat stone
of the same quality.
This exponential increase is for the simple reason that larger
the stone gets, the harder it is to find
Clarity refers to the relative purity of a diamond. Almost
all diamonds will contain a certain amount of impurities,
either internally in the form of inclusions, or on the surface
of the stone in the form of blemishes, i.e., small scratches
or nicks.
Diamonds with no surface blemishes or internal flaws are referred
to as flawless (FL) and command a very high price. Truly flawless
diamonds are extremely rare and almost every stone will contain
some kind of small inclusion.
Inclusions can be helpful in a number of ways. They provide
a unique 'fingerprint' and will allow anyone who is familiar
with a particular stone to immediately distinguish it from
any other.
The amount of inclusions present in a stone will start to
have a negative affect on the brilliance of a diamond when
you get towards the lower end of the clarity scale. Surface
blemishes and internal flaws affect how light travels through
a diamond and will therefore directly affect how much it sparkles.
The diagram below shows shows an illustration of the qualities
of diamonds:
(FL) Flawless
Shows no inclusions or blemishes of any sort under 10X magnification
when observed by an experienced grader.
(IF) Internally Flawless
Has no inclusions when examined by an experienced grader using
10X magnification, but will have some minor blemishes.
(VVS1 and VVS2) Very Very Slightly Included
Contains minute inclusions that are difficult even for experienced
graders to see under 10X magnification.
(VS1 and VS2) Very Slightly Included
Contains minute inclusions such as small crystals, clouds,
or feathers when observed with effort under 10X magnification.
(SI1 and SI2) Slightly Included
Contains inclusions (clouds, included crystals, knots, cavities,
and feathers) that are noticeable to an experienced grader
under 10X magnification.
(I1, I2, I3) Included
Contains inclusions (possibly large feathers or large included
crystals) that are obvious under 10X magnification and may
affect transparency and brilliance.
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