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Diamond Grading: The 4 C's
The 4 C's, when referring to diamond
value, are color, clarity, carat weight and cut. All
four factors are equally important in determining the
final cost of a diamond. The criteria for diamond grading,
most respected internationally, was developed by the Gemological
Institute of America (the G.I.A.). The terminology and
systems described on this page, are those of the G.I.A.
Following, is an explanation of these terms.
Color
The color of a diamond refers to the relative amount
of yellow, brown or gray body color that a stone possesses.
The G.I.A. scale starts at "D" and goes
through "Z", with "D" being void
of any body color, and "Z" having a light
yellow, brown or gray color.
With actual stones, the color difference
would appear like this:
Clarity
Practically all diamonds contain naturally occurring
internal characteristics called inclusions. The size,
nature, location and amount of inclusions determine
a stone's clarity grade and affect its cost. Clarity
is determined using 10X magnification. By definition,
if something is not visible at 10X, it does not effect
the clarity.
| Flawless |
VVS1 |
VVS2 |
VS1 |
VS2 |
SI1 |
SI2 |
I1 |
I2 |
I3 |
| Flawless/Internally Flawless= No inclusions
visible, by an expert at 10X magnification |
| VVS1-VVS2= Very, Very slight inclusions
very difficult for an expert to find under 10X |
| VS1-VS2= Very slight inclusions difficult
for an expert to find under 10X |
| SI1-SI2= Noticeable, relatively easy
to find under 10X. Not visible w/o magnification in
a face-up direction. |
| I1-I3= Obvious under 10X, may be visible
to the unaided eye, I3's inclusions may effect the
stone's durability. |
Carat
Weight
Carat is a unit of weight, not size. There are 5
carats in a gram. The weight of a diamond is measured
in carats. A carat is divided into 100 parts, called
points.
| 1 carat =1.00 carat=100points |
| 1/2 carat= 0.50 carat= 50 points |
1/4 carat=0.25 carat= 25 points
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Cut
At the turn of the last century, it was mathematically
determined, what the optimal proportions for a diamond
should be to assure maximum brilliance and dispersion.
Those proportions are as follows:
The quality of a diamond's cut makes all the difference
in how the stone appears. A poorly cut "D",
Flawless stone, can look dead and lifeless, whereas
an ideally proportioned diamond of much lower color
and clarity will appear radiant and dazzling. So,
why aren't all diamonds ideally proportioned? The
answer is quite simple. Diamonds are sold by weight.
Stones cut to ideal proportions waste more of the
diamond crystal, therefore weigh less than stones
that are cut to maximize weight. Here are examples:
The diamond below will weigh more because of the shallow
crown, and exaggerated table size. Not to mention,
that another diamond of shallow proportions could
be cut from the remaining crystal.
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