LEARN ABOUT DIAMOND CUT
Learn How Diamonds
Are Cut: Diamond Cutters must choose between More Weight or More
When a diamond crystal comes from the ground, the
brilliance, fire, and scintillation that constitute the unique beauty of a
polished diamond are still locked within it. The way in which a diamond
cutter decides to cut the new diamond ultimately determines the diamonds
beauty and brilliance.
The cut of a diamond is made up of many elements to
determine the quality of a diamond's cut. Gemological laboratories use
sophisticated measuring devices to determine how well a diamond is cut.
The Sarin Porportion Analyzer is used by GIA and
other gemological laboratories to analyze the following aspects of a
length, width & height,
measurements, depth percentage, table percentage, girdle
thickness, culet size, crown angle, crown height,
pavilion height, diamond symmetry.
The Cut Of A Diamond Is
The Most Important Element Of Diamond Beauty.
Learn Why Most Diamonds
Today Are Improperly Cut:
Many diamonds today are cut improperly. A flawless,
colorless rough diamond crystal can be cut to very fine or ideal proportions
to deliver the greatest balance of dispersion and brilliance, or it can be
cut to inferior proportions which yield a diamond that displays very little
brilliance but weighs slightly heavier.
Many people who buy diamonds today are unable to
identify a diamond with inferior cut. Because diamond cutters have financial
incentive not to remove weight from the rough diamond crystal, a great
amount of diamonds sold on the market today have heavy or deep cut.
Learn To Identify the Common Heavy or Deep
Diamonds are frequently cut for weight retention rather than to produce
maximum brilliance. These “undersize diamonds” often weigh more than if they
were cut correctly and can therefore can be sold for for a larger profit.
example: an ideal or very fine cut one carat diamond measures 6.4 to 6.5
millimeters in diameter. If you were to measure the diameters of most
one carat diamonds on the market today, you would find many to measure
between 5.9 and 6.3 millimeters.
These 1.00 carat, inferior cut “undersize
diamonds” are no larger in diameter than ideal or fine cut diamonds which
weigh 0.75 to 0.99 carats, and they exhibit significantly less brilliance.
We encourage you to choose a diamond that has ideal to very fine cut.
Understanding The Behavior Of Light In Diamond:
understand diamond cut, it helps to understand how light reacts within a
diamond. When light enters a diamond or any given material it bends or
refracts. The degree to which it bends is called the refractive index.
The refractive index of diamond is 2.41, the highest of any natural
transparent gem. In diamond the maximum angle of refraction is 24.5 degrees.
This is called the critical angle. Light traveling through a diamond is
reflected if it strikes a surface outside the critical angle. Light striking
a surface inside the critical angle will be refracted out of a diamond. The
critical angle is represented as 24.5 degree cone in the diagram.
In a well-made diamond, a high percentage of light entering through the
crown starts out striking the pavilion outside the critical angle. Thus it
is totally reflected to the other side of the pavilion. There it strikes
outside the critical angle again, and again and is totally reflected, this
time towards the crown, where it strikes within the critical angle and
leaves the diamond traveling in directions in which it can be seen. Such
controlled release of light is planned leakage. If the pavilion is too deep,
or too shallow, much of the light strikes inside the critical angle and
leaks out the back of the stone rather than reflecting through the diamond
and back through the top to the eye.
Learn What GIA & AGS Have To Say About Cut:
The Gemological Institute of America (GIA), and the American Gem Society
(AGS), two highly respected gemological institutions, have developed
different systems for evaluating diamond cut quality. GIA has defined
a range of proportion standards in which diamond cut quality is
classified... Currently GIA's diploma study courses teaches GIA students
seeking degrees in Gemology a system that assigns diamond cut grades in four
separate cut classes: (See illustration below) Please note, GIA's Gem Trade
Laboratory does not use the GIA cut class grade on its popular diamond
Guidelines For Ideal To Very Fine Cut In A Round Cut Diamond: (AGS 0 -
The Information included below is based on information
made available by Gemological Institute of America and
the American Gem Society. These two institutions are the
most honored in the world of gemological science.
This information below is a brief overview of diamond
cut, and what you should look for in regards to diamonds
of all shapes. Print this page and use it as a reference
when choosing your diamond. You can refer to the
diagrams to provide you with details that will help you
select a round brilliant cut diamond that has ideal to
very fine cut.
GIA’s Cut Classification System Defines CLASS 1 As Ideal To Very Fine
GIA’s research indicates that diamonds with slightly larger tables also
provide exceptional brilliance. Because of this evidence, GIA maintains its
current position not to specifically define ideal proportions as narrowly as
the Towkowsky theoretical ideal cut or AGS grade 0 ideal cut.
CLASS 1 = IDEAL
CLASS 2 = FINE
CLASS 3 = FAIR
CLASS 4 = POOR
Round Brilliant Cut Guidelines, Ideal To Very Fine Cut:
The AGS uses a system
that assigns a numerical grade from 0 to 10. 0 is considered perfect ideal
cut. 10 is the lowest grade. The AGS grade 0 is based on the Tolkowsky
The AGS 0 ideal cut will cost slightly more and fewer ideal cut diamonds are
available. Diamonds with proportions with the range of AGS 0 and 2 are
considered very fine cut and provide exceptional brilliance.
Fancy Shape Cut Guidelines, Ideal To Very Fine
Gemological Institute of America and the American Gem Society have not
conclusively determined or published ideal cut proportions in regards to
fancy cut diamonds. Information published by other sources has proven to be
Because fancy shaped diamonds are not symmetrical like a round diamond, a
broader range of parameters are needed in regards to proportion. It is with
great care that United Diamonds, has compiled this information.
The standards for fancy
cut diamonds shown in this diagram were determined by analyzing hundreds of
diamonds in fancy shapes. Fancy diamonds that fit into the ranges described
below offer the greatest amount of brilliance.
The Certified Gemologist-Appraisers carefully analyze every fancy shape
diamond that is requested by our customers. Every fancy shape must display
great brilliance in cut quality before the diamond is considered for
shipment to you. Hundreds of diamonds have been sold by United
Diamonds to very knowledgeable diamond buyers who expect a perfect to near
perfect cut. United Diamonds is very successful in delivering fabulous
fancy cut diamonds in every shape and size.