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Of all the 4Cs, cut has the greatest effect on a diamond’s beauty. In determining
the quality of the cut, the grader evaluates the cutter’s skill in the fashioning
of the diamond; technology. The more precise the cut, the more captivating the diamond
is to the eye.
Diamond cut is perhaps the most important of the four Cs, so it is important to
understand how this quality affects the properties and values of a diamond.The angles
and finish of any diamond are what determine its ability to handle light, which
leads to brilliance.
As shown in the images below, when a diamond is well-cut, light enters through the
table and travels to the pavilion where it reflects from one side to the other before
reflecting back out of the diamond through the table and to the observer's eye.
This light is the brilliance we mentioned, and it's this flashing, fiery effect
that makes diamonds so mesmerizing.
In a poorly cut diamond, the light that enters through the table reaches the facets
and then 'leaks' out from the sides or bottom of the diamond rather than reflecting
back to the eye. Less light reflected back to the eye means less brilliance.
Diamond Anatomy
Diameter: The width of the diamond as measured through the girdle.
Table: This is the large, flat top facet of a diamond.
Crown: The upper portion of a cut gemstone, above the girdle.
Girdle: The narrow rim of a diamond that separates the crown from the pavilion.
It is the largest diameter to any part of the stone.
Pavilion: The lower portion of the diamond, below the girdle. It is sometimes
referred to as the base.
Culet: The tiny facet on the pointed bottom of the pavilion, which is the
portion of a cut gem below the girdle.
Depth: The height of a gemstone, from the culet to the table.
Find out more about Diamond Cut from Wikipedia.
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Diamonds can have internal characteristics known as inclusions or external characteristics
known as blemishes. Diamonds without inclusions or blemishes are rare; however,
most characteristics can only be seen with magnification.
When we speak of a diamond's clarity, we are referring to the presence of identifying
characteristics on (blemishes) and within (inclusions) the stone.
If you think about the incredible amount of pressure it takes to create a diamond
and the fact that natural diamonds are not grown in a sterile laboratory, it's no
surprise that most diamonds have flaws.
Basically there are two types of flaws: inclusions and blemishes. Inclusions refer
to internal flaws and blemishes refer to surface flaws. However, in the diamond
grades listed below, you'll note that none of the grades include the term "blemish"
-- for the purposes of grading diamonds, all flaws are called "inclusions."
Inclusions include flaws such as air bubbles, cracks, and non-diamond minerals found
in the diamond. Blemishes include scratches, pits, and chips. Some blemishes occur
during the cutting processes (most often at the girdle). Diamonds with no or few
inclusions and blemishes are more highly valued than those with less clarity because
they are rarer.
Diamond Grading System for Clarity...
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Category
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Grade
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Flawless
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FL
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Internally Flawless
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IF
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Very Very Slightly Included
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VVS1
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VVS2
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Very Slightly Included
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VS1
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VS2
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Slightly Included
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SI1
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SI2
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Included
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I1
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I2
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I3
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F(Flawless): No internal or external flaws. Extremely rare.
IF(Internally Flawless): no internal flaws, but some surface flaws. Very
rare.
VVS1-VVS2(Very Very Slightly Included (two grades)): Minute inclusions very
difficult to detect under 10x magnification by a trained gemologist.
VS1-VS2(Very Slightly Included (two grades)): Minute inclusions seen only
with difficulty under 10x magnification.
SI1-SI2(Slightly Included (two grades)): Minute inclusions are visible under
10x magnification, and may be visible by the unaided eye.
I1-I2-I3(Included (three grades)): Inclusions visible under 10x magnification
AS WELL AS to the human eye. We do not recommend buying diamonds in any of these
grades.
Find out more about Diamond Clarity from Wikipedia.
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Gem-quality diamonds occur in many hues. In the range from colorless to light yellow
or light brown. Colorless diamonds are the rarest. Other natural colors (Blue, Red,
Pink for example) are known as fancy – their color grading is different than from
white diamonds.
When jewelers speak of a diamond's color, they are usually referring to the presence
or absence of color in white diamonds. Color is a result of the composition of the
diamond, and it never changes over time.
Because a colorless diamond, like a clear window, allows more light to pass through
it than a colored diamond, colorless diamonds emit more sparkle and fire. The formation
process of a diamond ensures that only a few, rare diamonds are truly colorless.
Thus the whiter a diamond's color, the greater its value.
To grade 'whiteness' or colorlessness, most jewelers refer to GIA's professional
color scale that begins with the highest rating of D for colorless, and travels
down the alphabet to grade stones with traces of very faint or light yellowish or
brownish color. The color scale continues all the way to Z.
Which Color Grade Should I Choose?
Diamonds graded D through F are naturally the most valuable and desirable because
of their rarity. Such diamonds are a treat for the eyes of anyone. But you can still
obtain very attractive diamonds that are graded slightly less than colorless. And
diamonds graded G through I show virtually no color that is visible to the untrained
eye.
And while a very, very faint hint of yellow will be apparent in diamonds graded
J through M, this color can often be minimized by carefully selecting the right
jewelry in which to mount your diamond. Keep in mind that, while most people strive
to buy the most colorless diamond they can afford, there are many people who actually
prefer the warmer glow of lower-color diamonds.
Grading fancy color diamonds
Yellow or brown color diamonds having color more intense than "Z", as well as diamonds
exhibiting color other than yellow or brown are considered fancy colored diamonds.
These diamonds are graded using separate systems which indicate the characteristics
of the color, and not just its presence. These color grading systems are more similar
to those used for other colored gemstones, such as ruby, sapphire, or emerald, than
they are to the system used for white diamonds.
Find out more about Diamond Color from Wikipedia.
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The carat is the diamond’s physical weight measured in metric carats. One carat
equals 1/5 gram and is subdivided into 100 points. Carat weight is the most objective
of the 4Cs. It involves no estimates, comparisons or judgments.
A carat is a unit of measurement, it's the unit used to weigh a diamond. One carat
is equal to 200 milligrams, or 0.2 grams.
The word "carat" is taken from the carob seeds that people once used in ancient
times to balance scales. So uniform in shape and weight are these little seeds that
even today's sophisticated instruments cannot detect more than three one-thousandths
of a difference between them.
The process that forms a diamond happens only in very rare circumstances, and typically
the natural materials required are found only in small amounts. That means that
larger diamonds are uncovered less often than smaller ones. Thus, large diamonds
are rare and have a greater value per carat. For that reason, the price of a diamond
rises exponentionaly to its size.
Find out more about Diamond Waight in Carat from Wikipedia.