Diamond Buying Guide
The key to making your diamond purchase with complete confidence and ease is understanding the fundamental
properties of a diamond, how each affects its beauty and cost, and
determining what balance is just right for you.
The Four C's
The "four C's" form the basis for evaluating a diamond and
determining it's value. Color, Clarity, Cut and
Carat are the four aspects involved. Each is important and impacts
the appearance of the stone in a different
way. With a basic understanding of these factors it will be possible
for you to determine the combination that
delivers the best value for you.
Color
The absence of color allows the most natural light to pass through
the diamond. Therefore, for most
preferences, the best color is no color at all, or "colorless". Most
diamonds have a lesser or greater
degree of yellow or brown color, sometimes so slight that it is
virtually imperceptible, while many others
on the market display more readily visible tints. Some rare diamonds
have very intense or exotic colors
(canary, pink, blue, green, purple, or even red) and can be
extraordinarily valuable.
Scale
A diamond's color is graded on an alphabetical scale from D-Z,
with D being absolutely colorless and Z being
light yellow. Beyond "Z", a diamond is considered to be an exotic or
"Fancy" color. Although many diamonds appear
to be colorless, the vast majority have at least a hint of body
color.
 If all other factors are equal, the less color in a diamond or the
higher color rating, the more valuable a
diamond becomes. Likewise, as the amount of color increases, the
price of a diamond decreases (though this does
not necessarily reduce the beauty of a diamond.)
Flourescence
Fluorescence, also known as photoluminescence, is a property in
some diamonds that makes them glow a certain
color (usually blue) when placed in an ultraviolet rich environment.
Strong, very strong and sometimes medium
blue fluorescence will tend to neutralize any yellowish or brownish
tint in diamonds 'H' in color or below
(I,J,K etc) giving them a whiter appearance. Such fluorescence in
some of the 'lower' color grades may even
enhance the value of these stones. Strong blue fluorescence in
diamonds will generally not improve the look of
a stone D to F in color may even detract a few percent from the value
of those diamonds. On rare occasions,
some diamonds with very strong blue fluorescence can have a hazy or
'milky' appearance that significantly reduces
their value. We always attempt to avoid offering such stones for
sale.
Impact on Beauty and Price
-
Impact on Beauty: Diamond color grades D through J are
considered colorless or nearly colorless, and
as such will make exquisite jewelry. D, E, and F colors, however
are the most highly prized as they are
considered "colorless." Please keep in mind that earrings and
pendants do not generally receive the same
scrutiny as the feature diamond in a ring. For that reason, you
might consider sacrificing a little in
color in exchange for greater size.
-
Impact on Price: Subtle differences in color may
account for dramatic differences in price.
When you are certain of the color grade of the diamond (per its
certificate and/or independent appraisal),
selecting a diamond that is a grade or two lower than another will
reduce the cost per carat and may allow
for the selection of a larger diamond - often with little if any
visible difference when the stone is
mounted.
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Clarity
Clarity is an indication of a diamond's purity. It describes quite
literally the degree to which a diamond is
free of imperfections. The clarity grades range from internally
flawless (IF) to highly imperfect (I3).
 Flaws in diamonds include "blemishes" and "inclusions." Blemishes
are an exterior imperfection on a diamond,
usually a feature of the cutting or polishing of the stone. Most
blemishes are so small as to have no affect on
the beauty or brilliance of the stone. Inclusions are tiny, usually
microscopic, imperfections inside a diamond.
In all diamonds, except the most rare, traces of minerals,
gasses or other elements were trapped inside
during the crystallization process. Inclusions may look like tiny
crystals, clouds, or feathers and are unique
to every diamond. Many of these birthmarks are not visible to the
naked eye. In fact, it is very rare to find a
diamond that is completely clean to the expert eye using
magnification.
The clarity of a diamond is graded by how many, how big (relative
to the size of the stone) and how visible the
inclusions are, and where they are located within the diamond. The
fewer and smaller the inclusions, the more rare
and valuable the diamond. Fewer than 1% of all diamonds ever found
have had no visible inclusions and can be called
internally flawless (IF).
Abbreviations
A diamond's clarity grade is described using the following
universally accepted abbreviations.
| Abbreviation | Definition | Description |
| F, IF | Flawless - Internally Flawless | Flawless stones have no external blemishes or internal
inclusions when examined by an experienced
grader using 10X magnification. Internally Flawless diamonds have
no inclusions under 10X magnification
but may have some minute external blemishes. |
| VVS1, VVS2 | Very, Very Slightly Included | Contains minute inclusions that are difficult for even
experienced graders to see under 10X
magnification. |
| VS1, VS2 | Very Slightly Included | Clean to the naked eye; contains minute inclusions when
examined under 10X magnification. |
| SI1, SI2, SI3* | Slightly Included | Ranges from clean to nearly clean to the naked eye (eye
clean) when viewed from the top.
|
| I1, I2, I3 | Included | Ranges from being nearly eye clean to having very easy to
find imperfections to the naked eye which
might affect the brilliance of the stone. |
Impact on Beauty and Price
-
Impact on Beauty:
The clarity grade of a diamond may have
little or no effect on the beauty of a diamond
if the clarity grade is within the first seven or eight grades
(Flawless-SI1 or SI2.) Most people can't
much visible difference among stones until reaching the
"imperfect" grades. Please keep in mind that
earrings and pendants do not generally receive the same scrutiny
as the feature diamond in a ring.
For that reason, you might consider sacrificing a little in
clarity in exchange for greater size.
-
Impact on Price:
As in color, small differences in clarity can
have a great impact on price. If beauty
is the chief concern, it is advisable to stick with a well made
diamond of SI1-2 clarity or better. Within
your budget, try to arrive at a good balance between overall
quality and size.
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Cut
Cut actually refers to two aspects of a diamond. The first is its
shape (round, marquise, etc) which is explained below, and the second is how well the cutting has been executed
which we will discuss here. The cut, or "make"
of a stone is one of the most important of all diamond
characteristics, and among the hardest to judge. The
proportions of a stone as well as its polish and precision of
faceting determine how much of the diamond's potential
fire and beauty may be released.
Diamond cutters are paid to maintain a balance between retaining
the maximum weight from rough stones and
cutting the finest possible diamond at the expense of "yield." Some
diamonds are cut exceedingly deep or shallow,
or are shaped to conform to the original shape of the rough stone. A
poorly made stone tends to result in a higher
yield (less waste) from the rough while a better made diamond
"wastes" more of the rough. A well-cut round diamond
typically weighs only about 40% or less of the original weight of the
piece of rough the cutter started with. This
is why better cut diamonds command a premium, and why Ideal Cut round
diamonds are the most valuable of all.
Ideal Cut Diamonds
An ideal cut has the highest quality cut proportions available to diamonds. It should also be noted that the
"ideal" and "premium" grades only apply to round brilliant cuts. There is considerably less agreement about the best
combination of proportions necessary for optimum performance in fancy shapes.
The way a diamond is cut profoundly influences its sparkle, fire
and brilliance, as well as its perceived size
and even, to some degree its apparent color. In order to maximize the
diamond's brilliance it must be well polished
and cut in a geometrically precise manner. This means properly
aligning the facets so light will enter the diamond
and reflect back through the large top facet, or table of the
diamond.
The most basic measurements of a diamond, expressed in millimeters
actually describe the following: minimum
width, maximum width (or length), and depth. These measurements are
important in matching stones for use in
earrings and other jewelry and for evaluating the cut quality of a
stone. All other features describing the
cut of a diamond, with the exception of polish, are based on the
stone's measurements.
Diamond Anatomy
Start by learning the "anatomy" of a diamond. The proportions of
these are critical measures in determining
the quality of a diamond's cut.
-
Facet:
The polished planes (surfaces) on the surface of the diamond,
defining its dimensions.
-
Crown:
The faceted portion of the diamond that is above the girdle.
The crown is generally the portion of the diamond that is visible above the setting.
-
Table:
The table is the top and largest facet of a polished diamond
through which much of the light both enters and exits.
-
Girdle:
The outermost edge of a diamond; it can be unpolished or
polished and faceted and of varying thickness. The girdle is generally where the diamond is held in a setting.
Girdles may be laser-inscribed with serial numbers, names, etc. without affecting the diamond's overall
brilliance or value.
-
Pavilion:
The portion of the diamond that is below the girdle.
-
Culet:
The small facet or point at the bottom of the pavilion of a
diamond.
Polish/Symmetry
Although most non-experts could never notice subtle differences in
polish or symmetry, noticeably asymmetrical
stones denoting poor symmetry are less attractive and less valuable -
just as a poor polish may detract from the
brilliance of a diamond and may actually leave slight streaks on the
surface. Below are some cut characteristics, and the effect they have on the overall quality of the diamond.
-
Symmetry:
Symmetry refers to the overall uniformity of the cut of a
diamond. Symmetry is based on the diamond's proportions, the relation of one facet to another. A diamond with
good symmetry can be more attractive than a less symmetrical stone. Stones with poor symmetry can actually
appear off-centered or noticeably out of round.
-
Polish:
The overall quality and uniformity of the polish of a
diamond. Its grade is based on the final finish applied to the facets and facet junctures by the cutter.
Well-polished diamonds permit maximum passage of light and prevent potentially streaky surfaces.
-
Table/Table Percentage:
The table is the top-most and generally the largest facet of
a diamond through which much of the light both enters and exits. A table that is too large or too small
will reduce the overall dispersion of a diamond's brilliance. In combination with other factors, the
table percentage is a significant component of a diamond's overall cut quality and value
-
Depth/Depth Percentage:
The depth is a measurement of the distance from the table to
the culet (bottom-most point). A depth
that is too shallow or too deep will allow light to escape through
the bottom of the stone, reducing the
stone's overall fire and brilliance. Depth percentage is a
significant component of the diamond's overall
cut quality and value.
-
Crown/Crown Angle:
The crown is the top portion of the diamond that lies above
the girdle. Crown % is a measurement that
relates the depth of the crown to the diamond's overall
depth.
-
Girdle:
The outermost edge of a diamond; it can be unpolished or
polished and faceted and of varying thickness.
Extremely thin or extremely thick girdles are less desirable than
more moderate girdles. The girdle is
generally where the diamond is held in a setting. Girdles may be
laser-inscribed with serial numbers,
names, etc. without affecting the diamond's overall brilliance or
value.
-
Culet:
The bottom-most facet or point of a diamond. Unless the culet
is abnormally large, it generally has
no impact on the value of a diamond.
-
Length/Width Ratio:
Applicable for fancy shapes (non-round). As you look down at
the stone, the length/width ratio
describes the shape of the profile. Although some ratios are
generally viewed as more desirable than
others for each fancy shape, the length/width ratio that is right
for you is a matter of personal
preference.
Impact on Beauty
A diamond's cut will most certainly influence
its fire (the lovely rainbow colors
that flash from within) and brilliance (the liveliness and
sparkle), as well as its perceived size and
even, to some degree its apparent color. The diagram below illustrates how different cuts reflect light in different
angles. A diamond must be cut in a
geometrically precise manner to
maximize its brilliance. On a classic round brilliant-cut diamond,
57 or 58 facets must be precisely
aligned so light will enter the diamond and reflect back through
the large top facet, or table of the
diamond.
 The percentage measurements for depth, height and crown are
important due to their impact on how light
passes through a diamond. Light should enter and exit a diamond
through the top facets. A cut that is
too shallow or too deep reflects it through the bottom facets, and
lets the light "leak" out of the bottom
or side of the gem. Please keep in mind that earrings and pendants
do not generally receive the same
scrutiny as the feature diamond in a ring. For that reason, you
might consider being a bit more open to
a slightly lower cut grade in exchange for greater size in these
items.
Impact on Price
When purchasing any diamond, carefully
consider the grade of the cut. For
round brilliant diamonds: ideal, premium, very good, good, fair, or
poor. For all other cuts: very good,
good, fair, or poor. Obviously, the cost of a diamond with will
increase with the quality of the cut.
Diamond cutters are generally paid to retain the maximum weight
from rough stones. A well-cut round
brilliant diamond typically weighs only about 40% or less of the
original weight of the piece of rough
stone the cutter started with. A poorly made stone tends to result
in a higher yield (less waste) from
the rough stone. This is why stones that are very well cut command
a significant premium.
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Carat
Diamonds are sold by the carat (ct), not to be confused with karat
(kt), which refers to gold purity. Jewelers
often refer to the carat weight of diamonds in terms of percentage
points. This is particularly true of stones under
one carat. There are 100 points to a carat, so if a diamond weighs 75
points, it is .75 of a carat.
Carat is a unit of weight, not area. Depending on the cut of a
stone, specifically its depth, a diamond weighing
.90ct could conceivably have a larger diameter than a 1.00ct stone
and therefore appear bigger. The comparative
size/weight illustration below gives an accurate comparison assuming
all stones are equally well cut.
 Note: This is the proportionate increase in size of
properly cut diamonds, not the actual size.
Impact on Price
- The price per carat of diamonds increases significantly with
size due to the rarity of larger gemstones,
particularly at popular size thresholds. For example, there is
little difference visually between a .95
carat diamond and a 1.00 carat diamond however the price difference
between the two can be significant
due to the 1.00 threshold.
- Also, as a rule, price increases per carat between smaller and
larger stones, due to the rarity of
larger gemstones. The larger the stone (all else being equal in
terms of overall quality), the more it
will cost per carat, not just the more it will cost overall due to
the number of carats it weighs. For
example, a top-quality two-carat stone could easily cost three to
four times as much as a one-carat stone,
not twice as much as one might expect. Again, this is due to the
increased rarity of larger sized
diamonds.
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Shapes and Styles
Today we can choose from many different stone shapes (also
referred to as "cuts") ranging from the classics to
newer silhouettes that appear as diamond cutters endeavor to create
new looks. Listed below are the eight most popular
and traditional cuts.
- Round Brilliant - the most classic cut
- Marquise - an elongated brilliant-cut stone with a point on
each end
- Princess - typically a four-sided square to slightly
rectangular brilliant cut
- Radiant - typically a slightly rectangular to square
diamond
- Emerald - a traditional octagonal cut usually rectangular
- Asscher - often referred to as a “square emerald cut,” this stone is step-cut and square, with cropped corners.
- Pear - combines the brilliance and form of a round stone with
the elongated elegance of a marquise
- Oval - reminiscent of the round brilliant cut, both in sparkle
and shape
- Heart - more fanciful cut, shaped just as it sounds
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Choosing the Ideal Setting
A diamond's setting will enhance the stone's appearance and
delight the wearer. It will also ensure that it is
mounted safely and securely.
Choosing the ideal setting will depend on the piece of jewelry,
the diamond you've selected, and of course, your
personal tastes and budget. Usually, there are two main decisions
regardless of the type of jewelry you are
creating - what type metal to choose for the mounting and how the
stone is secured in the mounting.
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Putting It All Together
Now, it is time to put it all together to balance and prioritize
which diamond qualities matter the most to your
individual purchase.
First you should set your budget. We have all heard the "two to
three months' salary" guideline for an engagement
ring, however only you can fairly assess your comfort level. We
would, however, recommend investing as much of your
budget as possible into the feature diamond in your jewelry. A better
quality, larger diamond that could be reset
in future years will continue to be a classic symbol of your love
forever.
Decide the relative importance to you of size versus quality. Do
you have a minimum specific size in mind?
Do you want the largest stone or the best quality stone for your
budget or somewhere in between? Given how you
feel about size versus quality, here are suggestions for how you
should balance the four "C"s. In each case, if
you determine your budget and search by the qualities shown -- the
results will show you what size diamonds are
available that meet your budget, size, and quality criteria. You can
then narrow down your choices by understanding
how the small differences between grades in each "C" affect the
beauty and the cost of the stone. You may want to
print out these pages for reference and to take notes as you search
for your diamond. Please keep in mind that
earrings and pendants do not generally receive the same scrutiny as
the feature diamond in a ring. For that reason,
you might consider sacrificing a little in quality in exchange for
greater size.
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Diamond Certification
Today, most fine diamonds weighing one carat or more are carefully
evaluated prior to being set, by a respected
laboratory such as the Gemological Institute of America (GIA) or the
American Gem Society (AGS) and are issued a
diamond grading report.
The diamond grading report, or "certificate" both certifies the
diamond as genuine and describes it in detail,
providing such important information as color grade, clarity grade,
carat weight, cutting and proportioning, etc.
If you are considering the purchase of a fine diamond weighing one
carat or more and it is not accompanied by
such a report, we strongly recommend that you have the stone
evaluated by a respected laboratory prior to
purchase. You should do so even if it means having a stone that is
already set removed from the setting and
reset. Given the significant difference in cost that can result from
a grading error in the more rare grades,
this procedure may well be worth the inconvenience and expense.
All loose diamonds offered by Ashford.com are accompanied by a
grading certificate or report from a leading
independent gemological lab such as:
- Gemological Institute of America (GIA) Gem Trade Laboratory
- American Gem Society (AGS)
Each of these labs conducts an independent examination of the
diamond and issues a certificate or report that
details their findings. You will receive the original certificate or
report with your diamond order.
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Appraisals
Do you provide appraisals on jewelry items?
We provide a professional appraisal on diamonds and diamond-related jewelry at no charge for any item priced $500 and over. We'll gladly perform an appraisal on similar items under $500 for a nominal charge.
The appraisal is an estimate of the approximate retail replacement value of your diamond or fine jewelry, which may be used for insurance coverage or other purposes. The appraisal report contains valuable information, including:
- An accurate and complete description of each article of jewelry being appraised
- The clarity, color and carat weight of the diamond or gemstone
- The shape of the diamond or gemstone (pear, round, princess, emerald, etc.)
- Type of precious metal setting (platinum, gold, etc.)
- Name of independent laboratory certification (GIA, EGL, AGS, HRD, IGI), if applicable
- Approximate current retail replacement market value
All appraisal reports from Ashford.com are signed by our Gemology experts, so you can be secure in the knowledge that the jewelry item you purchased is of the quality and value you expected. If you have any further questions about the appraisal report, please call us at 1-866-ASHFORD (274-3673) or send us an Online Inquiry.
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Caring for a Diamond
Diamonds may be the hardest substance known to man, but they too
can be damaged or dulled. For this reason,
it's important to learn about the care and cleaning of a diamond to
ensure its brilliance.
- Visiting your jeweler a minimum of once a year is highly
recommended. Professional cleaning is the best
option and it's important to have your jewelry checked occasionally
to make sure prongs haven't bent or
weakened. Other than professional care:
- Diamond jewelry should not be jumbled together or with other
pieces because diamonds can scratch other
jewelry and each other.
- Keep your diamond jewelry in a fabric-lined jewel case or in a
box with compartments or dividers.
- Even though a diamond is durable, a hard blow can chip it, so
avoid wearing a diamond when doing
rough work.
- Don't let your diamond come in contact with chlorine bleach or
other chemicals because they can pit or
discolor the mounting.
- Clean your diamonds regularly using either commercial jewelry
cleaner, a mix of ammonia and water, or a
mild detergent. Dip the jewelry into the solution and use a soft
brush to dislodge dust or dirt from under
the setting.
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