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The 4 C's are four
variables that are used to
calculate the value of a diamond
-- Clarity,
Color,
Cut, and
Carat Weight.
Clarity describes
the clearness or purity of a
diamond. This is determined by
the number, size, nature, and
location of the internal
(inclusions) and external
(blemishes) imperfections.
The clarity scale is broken down
into the following grades:
|
Symbol |
Meaning |
Definition |
|
F |
Flawless |
Free from all
inclusions or
blemishes. |
|
IF |
Internally Flawless |
No inclusions
visible at 10x
magnification. |
|
VVS1 |
Very Very Slightly
Included #1 |
Inclusions that are
extremely difficult
to locate at 10x. |
|
VVS2 |
Very Very Slightly
Included #2 |
Inclusions that are
very difficult to
locate at 10x. |
|
VS1 |
Very Slightly
Included #1 |
Minor inclusions
that are difficult
to locate at 10x. |
|
VS2 |
Very Slightly
Included #2
|
Minor inclusions
that are somewhat
difficult to locate
at 10x. |
|
SI1 |
Slightly Included #1 |
Noticeable
inclusions that are
easy to locate at
10x. |
|
Sl2 |
Slightly Included #2 |
Noticeable inclusion
that are very easy
to locate at 10x. |
|
I1 |
Included #1 |
Obvious inclusions.
Somewhat easy to
locate with the
unaided eye. |
|
I2 |
Included #2 |
Obvious inclusions.
Easy to locate with
the unaided eye. |
|
I3 |
Included #3 |
Obvious inclusions.
Very easy to locate
with the unaided
eye. |
The above clarity grading scheme
is in accordance with the GIA (Gemological
Institute of America). It
is important to note that the
GIA Grading system is not
static, and has changed slowly
over time.
Be aware!
Two methods used to enhance the
clarity grade given to a diamond
are laser drilling and fracture
filling. Laser drilling is the
process in which a laser is used
to drill a tiny hole into a
diamond and the black of the
imperfection is then removed.
The second treatment is fracture
filling. This method is not
permanent and therefore not
recommended. All clarity
treated diamonds must be
disclosed as such prior to
sale. Carolina Daimonds
does not deal with diamonds that
have been clarity treated in any
way.
Color
describes the amount of color
the diamond contains. This can
range from colorless to yellow
with slight tints of yellow,
gray or brown. Colors can also
range from intense yellow to
brown, blue, green, pink and
red. These fancy colors are rare
and therefore more valuable.
|
GIA |
COLOR -
COMMERCIAL GRADING |
D
E
F
G
H
I |
Colorless
(White) |
J
K
L |
Near Colorless
(White) |
|
M |
Faint Yellow |
|
N,O,P,Q,R |
Very Light Yellow |
S,T,U,V,
W,X,Y,Z |
Light Yellow |
Be aware! It
is possible to influence the
color by irradiation treatment
followed by heat treatment. This
method is not recommended for
two reasons. The first is the
risk involved with exposure to
irradiated objects. The second
is the risk of color change over
time. All color treated diamonds
must be disclosed as such prior
to sale. Carolina
Diamonds does not deal in
diamonds that have been enhanced
in any way.
The color of the stone can be
determined by using a
GIA (Gemological
Institute of America) Certified
set of master stones and/or the
Colorimeter, a computer which
accurately grades the color of a
polished diamond.
Cut
refers to the proportions,
finish, symmetry, and polish of
the diamond. These factors
determine the fire and
brilliance of a diamond.
Well cut
diamonds sell at a premium
and poorly cut diamonds sell at
discounted prices. With the
advent of technology, the cut of
the diamond can be determined
through the use of the
Dia-Mension system, a
computerized system which takes
accurate measurements and
proportions of a diamond in
seconds, in addition to the
standard millimeter gauge.
As an
example, a round brilliant cut,
which has 58 facets, is shown
below. Since the quality of the
cut is directly responsible for
the stone's beauty, the
precision with which the facets
are arranged is of prime
importance. They determine the
amount of light
reflected to the eye, called
brilliance.
The proportions displayed by the
stone are very significant. Two
of the key factors in the
grading of cut quality --
table
percentage and
depth
percentage -- are
usually expressed on grading
reports. Measurement of three
different parameters allows for
easy calculation of these
percentages by using the
formulas expressed below.
For example, for a round
brilliant cut diamond,
table
percentage is
calculated as follows:
Table (%) = longest table
measurement (in mm)
average girdle diameter (in
mm)
And for
depth
percentage:
Depth (%) =
depth (in mm)
average girdle diameter (in mm)
Without attention to
quality cutting, light is lost
and not returned to the eye.
Proportions Criteria are
as shown below:
|
|
"Premium Cut" |
"Tolkowsky Ideal
Cut" |
"Excellent Ideal
Cut" |
|
Total Depth |
58.8% - 63.8% |
58.0% - 63.8% |
59.2% - 62.4% |
|
Table Size |
58.0 - 61.0% |
53.0% - 58.0% |
52.5% - 58.4% |
|
Crown Height |
13.0% - 17.0% |
14.2% - 16.2% |
-------------- |
|
Crown Angle |
32.7° - 36.3° |
33.7° - 35.8° |
32.5° - 35.4° |
|
Pavilion Depth |
41.7% - 45.0% |
42.2% - 43.8% |
41.5% - 44.4% |
Each cut style above represents,
in the opinion of its respective
designer, those proportions
which best balance the qualities
of brilliance and dispersion
("fire") within a round diamond.
Carat is the unit of weight for the diamond. A carat is further subdivided in 100 points ( 0.01 carat = l point ). One carat is equal to 0.20 grams. Value per carat increases with carat size, because larger rough diamonds occur less frequently. In other words, 2 half-carat diamonds taken together will not cost as much as 1 one-carat diamond, as the one-carat stone is more rare. |
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