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Diamond.net » Consumer Resources »
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Learn everything you need to know about making a diamond purchase, directly from
the professionals. We have compiled an easy online Diamond Education Guide. Browse
the links below as a starting point to understanding what diamonds are all about.
If you would like to buy diamonds or diamond jewelry
click here»
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Beautiful and rare, diamonds are desired for their sparkle and message of love.
When you buy a diamond there are four points that you should consider, collectively
known as the Four C’s. Learn more »
Cut:
Refers to the symmetry and proportions of the stone; it is what gives the diamond
its sparkle. There are many diamond shapes to choose from. Whatever shape and quality
you prefer, a Laboratory Report should be a requirement for your engagement ring
or any significant diamond purchase. Learn more »
Color:
The most desirable diamonds are colorless. The best color is D, which is almost
clear white; the color scale descends from there through the alphabet toward Z,
moving further away from colorless toward yellow or brown tints. more
>
Clarity:
Diamonds have small imperfections in them known as inclusions; the fewer inclusions,
the more valuable the stone. Learn more »
Carat Weight:
This is the size of the stone. The word carat comes from the carob seeds that were
used to balance scales in ancient times. Learn more »
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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.
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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.
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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. Within the Well Cut standards
are the Diamonds.com sub categories of Ideal, Excellent, and Very Good.
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.
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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.
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Very Good
This range is balanced between precise proportions and price considerations. Viewed
by many as the best overall value in beauty and price.
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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.
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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.
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The best color is no color. Diamonds allow light to be reflected and dispersed as
a rainbow of color. This light dispersion, or color flash, has no effect on the
technical grading of color. The absolute finest colorless stone carries a D rating,
descending through each letter of the alphabet to Z, designating a diamond of light
yellow, brown, or gray. This body color may be caused by the presence of trace elements,
such as nitrogen, within the atomic framework of the carbon crystal. These trace
elements are so minute that they are scientifically measured in parts per million
(ppm). As the body color becomes more intense, the grade for color descends the
scale. These gradations are so minute and precise that discerning a single grade
(even by an expert) under less than ideal laboratory conditions is extremely difficult.
It is always best to compare diamonds graded by either the Gemological Institute
of America (GIA) or the American Gem Society (AGS) for accurate color grading. When
directly comparing diamonds for color, most consumers are unable to detect a difference
unless they are at least two or three color grades apart. We recommend selecting
a diamond with a color grade of K or better.
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Fancy Color
It is often surprising to learn that diamonds also occur by rare accidents of nature
in shades of pink, blue, green, amber, or even red. These rarely occurring colors
are referred to as fancies and are evaluated by a different set of color standards.
These standards take into consideration various factors such as hue and saturation.
Fancy colored diamonds are the most expensive because of their extreme rarity. Some
fancy colors can cost hundreds of thousands of dollars for diamonds of one carat
or less!
Fluoresence
Fluorescence is not directly related to a diamond’s color. This separate characteristic
refers to the diamond’s ability to fluoresce under ultraviolet (UV) light.
Our sun emits some UV light, but it is usually not great enough to detect fluorescence.
The most common source of UV is a black light. When exposed to UV light, many diamonds
will give off a distinctive glowing blue coloration. Although fluorescence may be
displayed in various colors, 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. Although fluorescence is a characteristic that can be measured,
it is seldom an issue when selecting a diamond.
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Almost all diamonds contain very tiny natural birthmarks known as inclusions. To
determine a diamond's clarity, an expert views it under 10 power magnification.
In addition to internal inclusions, surface irregularities are referred to as blemishes.
These two categories of imperfections-inclusions (internal) and blemishes (external)-make
up clarity.
The fewer the imperfections, the rarer and more valuable the diamond. Many inclusions
are not discernable to the naked eye and require magnification to become apparent.
A laboratory-certified clarity rating of SI2 represents the point at which inclusions
are technically not apparent to the average naked eye.
Contrary to popular belief, higher clarity does not always mean more beautiful.
If the inclusions are not visible to the naked eye, a higher clarity does not really
improve the appearance of a diamond but rather the rarity and price. A higher clarity
is more desirable and valuable, but knowing that you have selected the right clarity
for the right reasons is most important. We recommend a clarity of SI2 or better.
Clarity is graded using a very precise and complex method of evaluating the size,
location, and visibility of inclusions. The diagrams to the right show a top view
of a round diamond. The inclusions, shown in red, are an approximate sample for
each clarity rating. The plotted inclusions may not be actual size for display purposes.
Remember, the inclusions depicted in red are not visible to the average naked eye
until the I1-I3 clarities. Below is the technical clarity scale with a description
of each term.
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Most people compare carat weight to size. The larger the diamond the more it weighs.
The weight of a diamond is expressed in carats. The word carat originated from the
carob tree or Ceratonia siliqua. The tiny seeds of this tree are well known for
their uniformity and consistent weight. Traditionally diamonds and gemstones were
weighed against these seeds until the system was standardized, and one carat was
fixed at 0.2 grams. One carat is divided into 100 points. A diamond weighing one
quarter of a carat can also be described as weighing 25 points or 0.25 carats. Points
are generally not used to describe weights over one carat. Here are some examples
of different weights for round diamonds and their corresponding sizes. These may
not be actual size due to your monitor. The approximate girdle diameter is displayed
in millimeters.
How Size Effects Rarity
The rarity of a diamond is greatly affected by its size. The rarity of a 1.00 carat
diamond is much greater than twice that of a .50 carat. Although it only weighs
twice as much, the 1.00 carat is statistically much more difficult (rare) to mine
than the .50 carat. For an easy comparison of price and size, see the table below.
Prices are approximate and based upon D Color, internally flawless, excellent cut.
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Diamonds are cut in many different and exciting shapes. The shape of a diamond is
often confused with its cut. Shape refers to the basic form of the diamond: oval
or pear shaped, for instance. Cut or proportions, on the other hand, refer to the
ability of each of these shapes to reflect light. A round diamond, for example,
could have a good cut or a poor cut depending upon its proportions. When it comes
to shape, it is simply a matter of personal taste. The right shape for you is really
the one whose appearance you prefer. Shape can be a statement of whom you are; like
other areas of fashion, shape can reflect your individuality. The most popular shapes
are displayed here, but many new and interesting shapes are being developed every
year.
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The exact quality of a diamond is critical to its value. A diamond improperly graded
by only the slightest margin could dramatically affect its perceived value. Often
a conflict of interest may exist if someone grades the diamond who may serve to
gain or lose depending upon the outcome of the examination. It is important that
an independent gemological laboratory grade your diamond. Such a laboratory should
be internationally recognized for the highest standards and institutional ethics.
The Gemological Institute of America (GIA) and the American Gem Society (AGS) are
internationally known and respected as premier research, education, and gemological
grading institutes. The scientific grading reports provided by these laboratories
examine the 4 C’s: Cut, Color, Clarity and Carat-Weight. These reports are
recognized around the world as probably the finest opinions in existence.
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