Diamonds
THE FOUR C’s OF DIAMONDS
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:
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.
An Example of the Different Clarity Grades:
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.
An Example of the Different Clarity Grades:
Be aware! It is possible to influence the color by irradiation treatment followed by heat
treatment. All color treated diamonds must be disclosed as such prior to sale. The color
of the stone can be determined by using a GIA (Gemological Institute of America)
Certified set of master stones.
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.
Of the 4C's, the cut is the aspect most directly influenced by man. The other three are
dictated by nature.
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.
A diamond's ability to reflect light determines its display of fire and brilliance. A Round
Brilliant Diamond is usually cut with 57 or 58 facets, or separate flat surfaces
(depending on whether the culet was polished into a facet or closed to a point) divided
into 7 different parts. These facets follow a mathematical formula and are placed at
precise angles in relation to each other. This relationship is designed to maximize the
amount of light reflected through the diamond and to increase its beauty.
Above you will see different stone shapes however the shape of the stone is not the cut
of a stone 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. Too Shallow: Light is lost out
the sides causing the diamond to lose brilliance. Too Deep: Light escapes out the
bottom causing the diamond to appear dark and dull The diamond's proportions,
specifically the depth compared to the diameter, and the diameter of the table
compared to the diameter of the diamond, determine how well light will reflect and
refract within the diamond.
A Diamond is composed of:
Diameter: The width of the diamond as measured through the girdle.
Crown: The top portion of a diamond extending from the girdle to the table.
Girdle: The narrow band around the widest part of a diamond.
Pavilion: The bottom portion of a diamond, extending from the girdle to the culet.
Culet: The facet at the tip of a gemstone. The preferred culet is not visible with
the unaided eye (graded "medium" or "none").
Depth: The height of a gemstone measured from the culet to the table
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)
Proportions
What do we mean by "well-cut" and how do we distinguish our cut from "ideal" cut (or
"ultra ideal") diamonds? While we offer many diamonds which have proportions which
would be considered "ideal" cut, they are all very fine cut diamonds. However, unlike
the diamonds which fall within the "ideal cut" proportions, there are many diamonds,
which fall within those “numbers”, but whose cut is in fact poor and those diamonds are
not pretty diamonds. Like the Gemological Institute of America ("GIA") (see below), we
do not feel it is appropriate to use the term "ideal," as it reflects the concept of
"perfect." And we do not believe that all diamonds, which fall within the “ideal” cut
proportions, deserve the connotation that the term implies.
Every diamond lab has variations of what a beautifully cut diamond's proportions
should be. However, the GIA has done a recent study on the issues of cut and "ideal"
diamond" proportions. They have concluded that the use of the term "ideal" is not
appropriate as there are many different cutting parameters which will yield maximum
brilliance, depending on all of the other facets of the diamond's construction.
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. A quick check
is to compare the diamond's weight to a size chart. If the diamond was cut using the
above parameters it should be very close to the chart above. For example, a 1.00
round diamond should be approximately 6.5 mm. If a 1.00 carat diamond is only 6.3 mm
(too small) or 6.8 mm (too big) some of the diamond's parameters were compromised.
A well-cut diamond is beautiful because it's very brilliant. Of all the variables affecting
the value of a diamond, the cut is the most crucial.
Diamonds weighing less than 20 points are often called melee. Another term often
used is grain or grainer. A grain equals one-quarter (0.25) of a carat. For example, a
75-point diamond would be called in the trade a three grainer and a one-carat stone
may be called a four grainer. Loose stones are weighed directly on a scale but
mounted stones can only be estimated by plugging their measurements into a
mathematical equation.
Another quick way of estimating mounted round diamonds is by measuring the
diameter of the diamond and comparing it to a size
Since the price of diamonds is based upon rarity, the larger the stone the rarer the
diamond and the higher the price per carat. A one-carat stone is much rarer than two
half-carat stones, and is therefore considerably more expensive. However a smaller
stone of high quality can be more expensive than a lager stone of lesser quality.
GO TO TOP OF PAGE
BACK TO HOME PAGE
FOR INFORMATION AND PRICING
PLEASE CLICK HERE.
