BUYING DIAMONDS
How to Buy
a Diamond – The 4 Cs
There are four factors that determine the value of a diamond,
collectively known as the four “C”s. The combination
of the 4Cs determines each diamond's quality and value.
Master these important facts and you are prepared to make
your purchase.
Cut
The cut of a diamond refers to its proportions. Of the
4C's, the cut is the aspect most directly influenced by
man. The other three are dictated by nature. The geometric
proportions, or cut, of a diamond determine the amount
of sparkle a diamond emits. Quite often the cut of a diamond
is confused with its shape. Diamonds are cut into various
shapes depending upon the original form of the uncut diamond,
which is referred to as “rough.” Whatever
the shape, a well-cut diamond is better able to reflect
light.
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Making
the Cut
Light enters through the facets, or flat surfaces of a
diamond, and then exits the diamond in the form of fire,
or colored light, and white light, which is also called
brilliance. Round diamonds are the most popular diamond
shape, and round is the only shape capable of an “ideal”
cut. When diamonds are cut into a round shape and then
polished with care, they are uniquely capable of reflecting
all the light that enters them.
Cut
Determines Brilliance
The
figure below illustrates how light refracts in differently
cut round diamonds. If a round diamond is cut too deep
or too shallow, light is lost out the sides and bottom.
In a well-cut diamond, brilliance and fire are reflected
out of the top and sides of the diamond. Because good-,
very good-, and ideal-cut diamonds reflect the most light,
Pearl Gems carries these exclusively.
Diamond
Cut Grades
An
ideal cut produces the maximum amount
of reflected light. Because the round diamond is the only
shape that has complete symmetry — required for
100% light reflection — only round diamonds may
be graded as ideal cuts. This range is very strict and
combines the best in brilliance and fire. Technically,
the head of the class.
A very good cut reflects back nearly
all the light that enters the diamond. With the unaided
eye, you cannot see the difference between a very good
cut and an ideal cut round diamond, and even the differences
in measurement are minute. Because other diamond shapes
do not have 100% symmetry, very good is the highest cut
grade to be given to any fancy shape diamond, like oval,
emerald, or princess. A very good cut diamond is considered
an exceptionally proportioned, heirloom-quality gemstone.
This range is balanced between precise proportions and
price considerations. Viewed by many as the best overall
value in beauty and price.
A good cut describes a well-proportioned
diamond that reflects a good percentage of light. A diamond
with a good cut is appropriate as a jewelry gemstone.
A fair cut maximizes diamond weight at
the expense of fire and brilliance. A fair cut might reflect
as little as 40 percent of the captured light.
A poor cut results in a lifeless-looking
diamond. Poor-cut gemstones are not recommended for fine
jewelry.
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Diameter
The width of the diamond as measured through the girdle.
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Table
This is the large, flat top facet of a diamond.
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Crown
The upper portion of a cut gemstone, above the girdle.
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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.
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Pavilion
The lower portion of the diamond, below the girdle.
It is sometimes referred to as the base.
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Culet
The tiny facet on the pointed bottom of the pavilion,
which is the portion of a cut gem below the girdle.
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Depth
The height of a gemstone, from the culet to the table.
COLOR
A
colorless diamond reflects all colors of light. But a colorless
diamond is very rare; most diamonds contain slight traces
of yellow, brown, or gray, which limits the spectrum of
light that is reflected. So the less color present, the
more reflected light, and the better the color grade.
Grading
Color From D to Z
Diamonds
are graded on a letter scale from D to Z. The absolute finest
colorless stone carries a D rating, descending through each
letter of the alphabet to Z, designating a diamond of light
yellow, brown, or gray. This body color may be caused by
the presence of trace elements, such as nitrogen, within
the atomic framework of the carbon crystal. D, E, or F diamonds
have no color detectable to the unaided eye; those graded
G, H, I, or J are nearly colorless, but a trained gemologist
can detect a slight yellow cast. J through Z colored diamonds
have yellow or gray color visible to the unaided eye. Diamonds
rated lower than I have color that is detectable even to
the untrained eye. Those rated J to M have a trace of color,
while any diamond with an N or higher carries a noticeable
yellow tint. Buying a G or H color diamond rather than a
D or E color diamond will help you stick to your budget
without compromising appearance.
Fancy
Color
Although the great majority of diamonds come in shades of
white, the gems also come in a spectrum of majestic colors,
from pink, red and canary yellow to blue, green and brown.
These colorful diamonds, known as fancies, are valued for
their depth of color, just as white diamonds are valued
for their lack of color. Fancy colored diamonds are evaluated
by a different set of color standards, which take into consideration
various factors such as hue and saturation. Fancy colored
diamonds are the most expensive because of their extreme
rarity. After the color grade Z, you come to different grades
for fancy colored diamonds: fancy light, fancy, fancy intense
and vivid.
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CLARITY
Almost all diamonds contain very tiny natural birthmarks
known as inclusions. To determine a diamond's clarity, an
expert views it under 10 power magnification. In addition
to internal inclusions, surface irregularities are referred
to as blemishes. These two categories of imperfections-inclusions
(internal) and blemishes (external)-make up clarity.
The fewer the imperfections, the rarer and more valuable
the diamond. Many inclusions are not discernable to the
naked eye and require magnification to become apparent.
A laboratory-certified clarity rating of SI2 represents
the point at which inclusions are technically not apparent
to the average naked eye.
Contrary to popular belief, higher clarity does not always
mean more beautiful. If the inclusions are not visible to
the naked eye, a higher clarity does not really improve
the appearance of a diamond but rather the rarity and price.
A higher clarity is more desirable and valuable, but knowing
that you have selected the right clarity for the right reasons
is most important. We recommend a clarity of SI2 or better.
Clarity is graded using a very precise and complex method
of evaluating the size, location, and visibility of inclusions.
The diagrams to the right show a top view of a round diamond.
The inclusions, shown in red, are an approximate sample
for each clarity rating. The plotted inclusions may not
be actual size for display purposes. Remember, the inclusions
depicted in red are not visible to the average naked eye
until the I1-I3 clarities. Below is the technical clarity
scale with a description of each term.
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CARAT
WEIGHT
Most
people compare carat weight to size. The larger the
diamond the more it weighs. The weight of a diamond
is expressed in carats. The word carat originated
from the carob tree or Ceratonia siliqua. The tiny
seeds of this tree are well known for their uniformity
and consistent weight. Traditionally diamonds and
gemstones were weighed against these seeds until the
system was standardized, and one carat was fixed at
0.2 grams. One carat is divided into 100 points. A
diamond weighing one quarter of a carat can also be
described as weighing 25 points or 0.25 carats. Points
are generally not used to describe weights over one
carat. Here are some examples of different weights
for round diamonds and their corresponding sizes.
These may not be actual size due to your monitor.
The approximate girdle diameter is displayed in millimeters.
The rarity of a diamond is greatly affected by its
size. The rarity of a 1.00 carat diamond is much greater
than twice that of a .50 carat. Although it only weighs
twice as much, the 1.00 carat is statistically much
more difficult (rare) to mine than the .50 carat.
For an easy comparison of price and size, see the
table below. Prices are approximate and based upon
D Color, internally flawless, excellent cut. |
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