Understanding Diamonds – the 4 Cs
Let the 4 Cs (cut, clarity, color & carat weight) be your guide in determining diamond quality.
It is from these characteristics that you can determine the value of a diamond.
Cut
Clarity
Carat Weight
Many people confuse cut with the shape of the diamond. Diamonds are 100% carbon, formed in the earth by
Our diamonds are cut with a full 58 facets (fancy cuts millions of years of heat and pressure. Nature’s
may vary). A precision-cut diamond with the correct imperfections are inclusions or flaws that appear in this
proportions and angles is designed to give the maximum process and affect the stone’s clarity. A diamond that is
amount of light, brilliance, fire and, therefore, ultimate virtually free of these flaws is of the highest quality, for
beauty. nothing interferes with the passage of light through it.
Diamonds are cut into a number of shapes, depending
on the nature of the rough stone and the position of the
inclusions.
Thus, the fewer number of flaws in a diamond serves
only to intensify its fire and beauty.
Diamonds can be found in all shapes and sizes. One
carat is divided into 100 points, so that a diamond of
50 points weighs .50 carat or one-half carat. Size is the
most obvious factor in determining the value of a
diamond, but bigger is not necessarily better. Diamonds
of equal size can have very unequal values depending
on their quality. Diamonds of fine quality can be found
in all sizes.
All of our diamonds have been selected according to their
clarity, color and cut to ensure quality, beauty and value.
At Costco, we state the minimum amount of diamond
weight in each piece on each appraisal, and in most
cases the actual weights are greater.
Photos and charts courtesy of the Gemmological Institute of America.
To determine a diamond’s clarity, it is viewed under a
10-power magnification by a trained professional.
Minute inclusions neither mar its beauty nor endanger
its durability.
Lab-Created Emeralds
We guarantee that all diamonds at Costco are rated VS2
(very slightly included) or better. This rating is what we
consider to be the best rating in determining value to
quality.
Synthetic (lab-created) emeralds were invented in
1935, and first became popular in the 1960s, due
to a worldwide shortage of fine-quality natural
emeralds.
Clarity Chart
Industry Grading Guide
VERY VERY VERY
INTERNALLY SLIGHTLY SLIGHTLY SLIGHTLY
FLAWLESS INCLUDED INCLUDED INCLUDED IMPERFECT
IF VVS1 VS1 VS2 SI-1 SI-2 I1 I2 I3
VVS2
Color
Lab-created emeralds are physically, optically and
chemically identical to natural stones. The color of
the lab-created emerald is that of a very-fine natural
emerald. The hardness of the stone is exactly that of
a natural stone as well.
Only a highly-trained gemologist, using magnification,
can distinguish between the synthetic emerald and
the natural.
The laboratory growing process can take up to six
months.
Diamond Quality
Quality is as important in diamonds as in anything else
you own. When purchasing diamond jewelry, you will
want the diamonds, no matter what their size, to be the
best quality possible. At Costco, we are committed to
making sure our diamonds are of consistently fine
quality. We are so sure of the quality of our diamonds,
we supply a written description with each diamond
purchase stating the quality and diamond weight of
each piece.
How can we be so sure of our quality?
Simple. We have established our own quality-control
center where each piece of jewelry is closely examined
by highly qualified people who have many years of
experience in all areas of the jewelry industry. This
allows us to maintain our high quality standards.
How to judge the value of a diamond?
Let the 4 Cs (cut, clarity, color and carat weight) be
your guide in determining diamond quality.
The best color for a diamond is no color. It is the
totally colorless diamond that acts as a prism, allowing
light to pass effortlessly through it and be transformed
into rainbows of color. The color scale (shown below)
grades from a high of colorless to a low of fancy yellow.
The difference between one grade and another is very
subtle, as can be seen by the number of grades within
any one category.
Color Chart
Color scale in order of best to worst color
LIGHT
YELLOW
NEAR SLIGHTLY VERY LIGHT TO FANCY
COLORLESS COLORLESS TINTED YELLOW YELLOW
DEF GHI J KLM NOP STVW
Q R XYZ
Costco’s diamonds range from colorless to near
colorless and the bottom of our color scale is I, not
J. We recommend the I to ensure we have a true
near-colorless diamond without the chance of
having a slightly tinted diamond in our selection.
This I rating is the point at which the best price, or
value-to-quality ratio is attained.
APRIL 2005 • The Costco Connection 1
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