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. 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.
Diamonds are usually cut with 58 facets, or separate flat surfaces. 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.
Well Cut
When a diamond is cut to proper proportions, light is reflected from one
facet to another and then dispersed through the top of the stone.
Deep Cut
When the cut of a diamond is too deep, some light escapes through the
opposite side of the pavilion.
Shallow Cut
When the cut of a diamond is too shallow, light escapes through the pavilion
before it can be reflected.
The cut, or proportion, of a diamond is measured in percentages relative
to the diameter of its girdle. The girdle diameter of each diamond is
always considered 100%. Example: The girdle of a diamond measures 10 millimeters
(100%). The table measures 5.6 millimeters. The total depth measurement
is 6.1 millimeters. The diamond would be described as having a table of
56% and a depth of 61%. The table and depth percentages are the key to
determining good proportions.
Ideal
This range is very strict and combines the best in brilliance and fire.
Technically, the head of the class.
Excellent
This range is also of great beauty yet slightly more flexible regarding
percentages. Many experts prefer the appearance of this range to Ideal.
Very Good
This range is balanced between precise proportions and price considerations.
Viewed by many as the best overall value in beauty and price.
HOW DO I KNOW IF A DIAMOND IS WELL CUT?
A well cut diamond is the secret to a beautiful and brilliant diamond.
Like beauty itself, the true meaning of “well cut” is often
found in the eye of the beholder. While you may prefer a particular set
of proportions, someone else might prefer slightly different proportions.
Personal preference, even among experts, will always be an issue in defining
the best cut.Think of Ideal, Excellent and Very Good as rings in a bull's
eye. These classifications for cut represent an acceptable range for that
category. The ranges narrow as you move toward Ideal at the center. Ideal
has the narrowest range, with Excellent slightly larger and Very Good
the largest. All three of these categories fall within the "well
cut" classification.
In many cases the visual differences from
one classification to the next are so small they may be indiscernible
to the naked eye. Science has produced sophisticated machinery that can
measure every aspect of a diamond’s proportions. It is this precision
that allows such strict standards to be defined. These guidelines give
you the ability to not only make a selection regarding cut but to understand
the underlying science upon which it is based. In any case a brilliant
and scintillating diamond is ultimately the goal.
The Lowest score becomes the overall cut grade. In order to classify each
diamond with an overall cut grade the lowest assigned grade for any individual
characteristic is always used. For example: If the table percentage falls
within Ideal yet the depth percentage is in the Very Good range, the diamond
is classified as Very Good.
The proportions are not the same for every shape. Many of the diamond
shapes require their own guidelines in order to achieve maximum beauty.
Due to the mathematical differences inherent in different shapes, the
table and depth guidelines are formulated to maximize fire and brilliance.
Although the numbers may be different, the goal is the same: a magnificent
display that highlights the individuality and character of each shape.
Girdle
The girdle is the outer edge of a diamond. It usually has a frosted appearance.
Many diamonds are also finished with a fully polished or even a faceted
girdle. This characteristic does not affect the value of a diamond and
is often more a reflection the diamond cutter's preference. The girdle
is rated in terms of thickness. Girdle size is generally defined as either
Extremely Thin, Very Thin, Thin, Medium, Slightly Thick, Thick, Very
Thick, or Extremely Thick. The girdle can also be described
as a range of these terms such as Thin to Thick. Avoid the two Extremes.
When purchasing a diamond, select one with a girdle that is neither Extremely
Thin nor Extremely Thick.
Culet
The culet is the bottom point of the diamond. In many cases this point
actually has a very small facet. The culet is referred to in terms that
relate to the presence or size of this facet. The culet is generally graded
as None or Pointed, Very Small, Small, Medium, Slightly Large,
Large, Very Large, and Extremely Large. Smaller is more
desirable.
Polish
This characteristic refers to the finishing or final polishing of the
facets, or flat surfaces. Contrary to common belief, diamonds are ground
and polished, not chipped away, until they reach their final form. Each
facet should be carefully fashioned by the diamond cutter to shine and
be free from polishing imperfections. The polish of a diamond is generally
defined as either Poor, Fair, Good, Very Good, or Excellent.
When purchasing a diamond, select one with a polishing grade of Good or
above.
Symmetry
This characteristic refers to the alignment and positioning of the facets,
or flat surfaces. Each facet should be carefully positioned by the diamond
cutter in proper proportion and relationship to the other facets. The
alignment of each facet should be sharp and precise; improperly joined
facet junctions can make a diamond appear uneven. The symmetry of a diamond
is generally defined as either Poor, Fair, Good, Very Good, or
Excellent. When purchasing a diamond, select one with a symmetry
grade of Good or above.
Fluoresence
This characteristic refers to the diamond’s ability to fluoresce
under ultraviolet light. When exposed to UV light, many diamonds will
give off a distinctive glowing blue coloration. Although fluorescence
may be displayed in various shades, blue is the most common in diamonds.
The fluorescence of a diamond is defined by its intensity as either None,
Faint, Medium, Strong, or Very Strong. Most of the time
fluorescence isn't an issue unless the intensity is Strong or Very Strong.
In the very high colors D, E, and F, Strong fluorescence is considered
less desirable. Ironically, in slightly lower colors of J and below. Strong
fluorescence is desirable.
