1. Color
Key Points
Color refers to a diamond's lack of color, grading the whiteness of a diamond.
A color grade of D is the highest possible, while Z is the lowest.
Blue Nile only sells diamonds with a color grade of J or higher.
Color manifests itself in a diamond as a pale yellow. This is why a diamond's color grade is based on
its lack of color. The less color a diamond has, the higher its color grade. After cut, color is generally
considered the second most important characteristic when selecting a diamond. This is because the
human eye tends to detect a diamond's sparkle (light performance) first, and color second.
At Blue Nile, you'll find only the finest diamonds with color graded D-J. Diamonds graded J or better
are colorless or near-colorless, with color that is typically undetectable to the unaided eye.
Z-N Noticeable color. Not carried by Blue Nile.
M-K Noticeable color. Not carried by Blue Nile.
J-I Near-colorless. An exceptional value with slightly detectable warmth or tone.
H-G Near-colorless. Color difficult to detect unless compared side-by-side against diamonds
of better grades. An excellent value.
F-E Colorless. Minute traces of color can be detected by an expert gemologist. A rare
diamond.
D Absolutely colorless. The highest color grade. Extremely rare.
What Color is Right for Me?
For the purist, look for a colorless diamond with a grade of D-F for a diamond with no
discernible color.
For an excellent value in a diamond with little or no noticeable color to the unaided eye, look
for a near-colorless grade of G-I

2. Carat
Key Points
Carat is specifically a measure of a diamond's weight, and by itself may not accurately reflect a
diamond's size.
We tend to evaluate diamond size by viewing it from the top because that is how diamonds are
presented to us when set into a ring.
To understand diamond size, carat weight should be considered in conjunction with two other
criteria:
o – Distance in millimeters across the top of the diamond.
o – Diamond's cut grade.
As the name suggests, carat weight specifically refers to a diamond's weight. However, much as
a person's weight does not necessarily correlate with height, carat weight, by itself, may not
accurately reflect a diamond's size. To gain a precise understanding of diamond size, Blue Nile
recommends considering carat weight with two other characteristics: 1) the distance across the
top of the diamond measured in millimeters, and 2) the diamond's cut grade.
It is important to measure the distance across the top of the diamond as this is how we view a
stone when set into a ring.
A diamond's cut grade should also be considered because, as we noted in the cut grade
section, when a diamond is cut with the proper proportions, the maximum amount of light (or
sparkle) is returned out of the top of the diamond. Thus, when a diamond is well cut, the light
reflected out of the top makes it appear larger. In addition, much of the weight of a poorly cut
diamond, for example, may be "hidden" in the base of the diamond, making the diamond appear
smaller than its carat weight would imply.
It is therefore possible to have a diamond of a lower carat weight, but higher cut grade, that
appears larger than a diamond with a larger carat weight, but poor cut.
Once you've selected your cut, color, and clarity grade, it's easy to determine the carat weight of
diamond that will fit within your budget.
Much as there are 100 pennies in a dollar, a one-carat diamond is comprised of 100 points.
Hence, 50 points is equal to 1/2-carat, and so on.
This chart illustrates how diamonds of different carat weights look when set in a ring. Note that a
2-carat diamond does not appear to be twice the size of a 1-carat diamond when viewed from
the top.

3. What Carat Weight Is Right For Me?
To choose the best carat weight of diamond, consider the size of her finger, the size of your setting, and
your budget.
If a large carat weight is important to you, yet you're working within a strict budget, consider a
diamond with a good cut, SI1-SI2 clarity, and an I or J color grade.
Diamond prices jump at the full- and half-carat weights. Diamonds just below these weights cost
significantly less, and, because carat weight is distributed across the entirety of the diamond,
small size differences are almost impossible to detect.
Keep in mind that the smaller the finger, the larger the diamond will appear. A 1.5-carat diamond
solitaire looks much larger on a size 4 finger than a size 8.
Not all settings will fit all diamond carats or shapes. If you have already selected a setting, check
the diamond specifications of your ring or ask your Blue Nile Diamond and Jewelry Consultant
(888-565-7641) for help. If you need a special jewelry piece created, Blue Nile can accommodate
almost any request.

4. Clarity
Key Points
Clarity is a measure of the number and size of the tiny imperfections that occur in
almost all diamonds.
Many of these imperfections are microscopic, and do not affect a diamond's beauty in
any discernible way.
Much is made of a diamond's clarity, but of the Four Cs, it is the easiest to understand, and,
according to many experts, generally has the least impact on a diamond's appearance. Clarity
simply refers to the tiny, natural imperfections that occur in all but the finest diamonds.
Gemologists refer to these imperfections by a variety of technical names, including blemishes
and inclusions, among others. Diamonds with the least and smallest imperfections receive the
highest clarity grades. Because these imperfections tend to be microscopic, they do not
generally affect a diamond's beauty in any discernible way.
Flawless, Internally Flawless: No internal or external imperfections. Internally
FL, IF Flawless: No internal imperfections. Very rare.
Very, Very Slightly Included: Very difficult to see imperfections under 10x
VVS1,
magnification. An excellent quality diamond.
VVS2
Very Slightly Included: Imperfections are not typically visible to the unaided
VS1,
eye. Less expensive than the VVS1 or VVS2 grades.
VS2
Slightly Included: Imperfections are visible under 10x magnification, and may
SI1,
be visible with the unaided eye. A good diamond value.
SI2
Included: Blue Nile does not carry diamonds of I-grade clarity.
I1, I2, I3

5. What Clarity Grade Is Right For Me?
Select an "eye-clean" diamond - one that has no imperfections visible to the unaided eye. An
excellent value, diamonds of this clarity are much less expensive than flawless (FL) or
internally flawless (IF) diamonds, which are extremely rare and command higher prices.
Frequently, imperfections in diamonds graded slightly included (SI) are not visible to the
unaided eye, making them an excellent value. If you're considering a diamond with an SI
clarity grade, call to speak to a diamond and jewelry consultant who will review the diamond
to ensure the imperfections are not visible to the unaided eye.

6. Cut
Key Points
Cut is a diamond's most important characteristic.
It has the greatest overall influence on a diamond's beauty.
It determines what we generally think of as sparkle.
Blue Nile gemologists recommend selecting the highest cut grade within your budget. The reason is
simple: of the Four Cs, no other characteristic has a greater influence on a diamond's appearance.
A diamond's cut grade is an objective measure of a diamond's light performance, or, what we
generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out
of the top of the diamond (which gemologists refer to as the table). If it is cut too shallow, light leaks
out of the bottom; too deep and it escapes out of the side.
Cut Grades
Blue Nile Signature Ideal cut: Our most brilliant cut, representing roughly the top 1% of diamond
quality based on cut. The highest grades of polish and symmetry allow it to reflect even more light
than the standard ideal cut.
Ideal cut: Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all
light that enters the diamond. An exquisite and rare cut.
Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly
as much light as the ideal cut, but for a lower price.
Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light
that enters. Much less expensive than a very good cut.
Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality
diamond, but a fair cut will not be as brilliant as a good cut.
Poor cut: Diamonds that are generally so deep and narrow or shallow and wide that they lose
most of the light out the sides and bottom. Blue Nile does not carry diamonds with cut grades of
poor.
What Cut Grade Is Right For Me?

7. For the best possible cut, look to the Blue Nile Signature Collection. Custom made exclusively for
Blue Nile, each Signature Collection diamond is hand-selected and cut to the most exacting
standards, guaranteeing one of the finest cuts available in the world.
Diamonds with a cut grade of good or very good represent an excellent combination of beauty
and value.

8. Shape
Round
The round brilliant cut diamond is by far the most popular and most researched diamond shape
available today. For almost 100 years, diamond cutters have been using advanced theories of
light behavior and precise mathematical calculations to optimize the fire and brilliance in a round
diamond. In addition to being the most popular and researched shape, a round diamond will
typically give you more flexibility in terms of balancing cut, color, and clarity grades while still
getting the fire and brilliance you want.
To maximize the brilliance of a traditional round diamond, select one in the two highest cut
grades, ideal or very good, and choose ideal, excellent, or very good polish and symmetry
grades.
Princess
This is our most popular non-round diamond. Its beautiful brilliance and unique cut makes it a
favorite for engagement rings. The princess has pointed corners and is traditionally square in
shape. When choosing a color grade, consider that while the price of a J-color non-round
diamond is exceptional, color may be slightly visible in its corners. Also, princess-cut diamonds
can vary greatly in how square or rectangular they are. To find the dimension of princess you
want, look for the length-to-width ratio in our interactive diamond search and on each diamond's
detail page. This will determine what the diamond will look like when viewing it from above. Here
are length-to-width ratios for princess-cut diamond shapes that are pleasing to the eye.
For a princess diamond shape that is square, look for length-to-width ratios between 1 and 1.05.
If you prefer more of a rectangular shape, look for length-to-width ratios greater than 1.10.
Emerald
What makes this shape different is its pavilion, which is cut with rectangular facets to create a
unique optical appearance. Due to its larger, open table, this shape highlights the clarity of a
diamond. If you choose an emerald-cut with a lower clarity grade, such as SI, be sure to review
the clarity plot on the diamond certificate. Also, emerald-cut diamonds can vary greatly in how
rectangular they are. If you'd prefer an emerald cut with a squared outline, look for an Asscher-
cut diamond. To find the shape of emerald you want, look for the length-to-width ratio in our
interactive diamond search and on each diamond's detail page. The length-to-width ratio will
determine the diamond's outline, or what it will look like when viewed from the top.
For the classic emerald-cut shape, look for a length-to-width ratio between 1.30 and 1.40.

9. Asscher
This beautifully unique shape is nearly identical to the emerald-cut, except that it is square.
Also, this shape has a pavilion that is cut with rectangular facets in the same style as the
emerald-cut. If you choose SI-clarity be sure to view the clarity plot on the diamond certificate,
because this shape highlights the clarity of the diamond. When choosing a color grade, consider
that while the price of a J-color non-round diamond is exceptional, color may be slightly visible
in its corners.
All Asscher-cut diamonds from Blue Nile will appear square, because each one is guaranteed to
have a length-to-width ratiobetween 1.00 and 1.05.
Marquise
The shape of a marquise diamond can maximize carat weight, giving you a much larger-looking
diamond. This brilliant-cut diamond looks beautiful set with round or pear-shaped side stones,
and the length of the marquise makes fingers appear long and slender. To find the dimension of
marquise you want, look for thelength-to-width ratio in our interactive diamond search and on
each diamond's detail page. The length-to-width ratio will determine the diamond's outline, or
what it will look like when viewed from the top.
For the most traditional marquise-cut diamonds, look for length-to-width ratios between 1.75 and
2.25.
Oval
An oval diamond has beautiful brilliance that's similar to a round diamond. Oval diamonds are
also very popular as their length can accentuate long, slender fingers. To find the dimension of
oval you want, look for the length-to-width ratio in our interactive diamond search and on each
diamond's detail page. The length-to-width ratio will determine the diamond's outline, or what it
will look like when viewed from the top.
For the most traditional oval diamonds, look for length-to-width ratios between 1.33 and 1.66.
Radiant
Trimmed corners are the signature of this diamond, and they help make the radiant-cut a
popular and versatile choice for jewelry. A radiant-cut looks equally beautiful set with either
baguette or round side-diamonds. Radiant-cut diamonds can vary in their degree of
rectangularity. To find the dimension of radiant you want, look for the length-to-width ratio in our
interactive diamond search and on each diamond's detail page. The length-to-width ratio will
determine the diamond's outline, or what it will look like when viewed from the top.
For a radiant diamond shape that is square, look for length-to-width ratios between 1 and 1.05.
If you prefer more of a rectangular shape, look for length-to-width ratios greater than 1.10.
Pear
This brilliant-cut diamond is also called a teardrop for its single point and rounded end. The
unique look of the pear shape helps make it a popular choice for a variety of diamond jewelry. If
you choose an elongated pear shape, the length of the diamond creates a subtle slimming
effect on the fingers.

10. To understand what the diamond will look like when viewing it from above, look for thelength-to-
width ratio on each diamond's detail page. For the most traditional pear-shaped diamond, look
for a length-to-width ratio between 1.45 and 1.75.
Heart
The heart is the ultimate symbol of love. The unique look of the heart-shaped diamond helps
make it a distinctive choice for a variety of diamond jewelry. When choosing a color grade,
consider that while the price of a J-color heart shaped diamond is exceptional, color may be
slightly visible in its corners. To find the dimension of heart-shape you want, look for the length-
to-width ratio in our interactive diamond search and on each diamond's detail page. The length-
to-width ratio will determine the diamond's outline, or what it will look like when viewed from the
top.
Cushion
This unique shape has been popular for more than a century. Cushion-cut diamonds (also
known as "pillow-cut" diamonds) have rounded corners and larger facets to increase their
brilliance. These larger facets highlight the diamond's clarity, so if you choose an SI clarity
grade, be sure to review the clarity plot on the diamond certificate. Cushion-cut diamonds are
available in shapes ranging from square to rectangular. To find the dimension of cushion you
want, look for the length-to-width ratio in our interactive diamond search and on each diamond's
detail page. The length-to-width ratio will determine the diamond's outline, or what it will look like
when viewed from the top.
For a cushion-cut diamond that is square, look for length-to-width ratios between 1 and 1.05. If
you prefer more of a rectangular shape, look for length-to-width