The value of a diamond is determined by
its Cut, Color, Clarity and Carat, also known as the classic "Four C's".
Understanding such criteria as diamond grading reports and the factors
affecting a diamond's cost will help the buyer make a confident and sound
decision when making a purchase.
Cut refers to the proportions and shape of the finished diamond, and is
the most important factor in determining the brilliance of a diamond. A
classic round brilliant cut diamond has 58 facets - 33 on the top, 24 on
the bottom and the culet (1 point at the bottom - another tiny facet).
The
finished diamond should be symmetrical. The table should be symmetrical,
well-centered, and flat, not sloping. The cutlet should be centered when
viewed from the top. The crown and pavilion facets should be in exact geometric
relation to one another. And, the girdle should be perfectly round exhibiting
a straight edge when viewed from the side.
Too
Shallow
Diamonds that are cut too thin or shallow allow the light to pass through
the sides of the diamond and appear lifeless, dull, or flat in the center.
Too Deep
Diamonds that are cut too deep or high do not reflect enough light back
through the top of the diamond and appear to be dark in the center.
Deciding on a shape is a very important step in the selection process of
your diamond. Following are some examples of the classic shapes of diamonds:
Round
The round brilliant diamond is the most popular diamond shape, the
most brilliant of all the cuts, and is the most expensive.
Round diamonds are most often found in engagement rings and are popular
as stud earrings and in pendants.
Princess
Most people like the Princess because it is rectangular and yet has
some of the sparkle of a Round brilliant cut.
The princess cut may have either 50 facets (21 crown, 4 girdle, 25
pavilion) or 58 facets (21 crown, 4 girdle, 33 pavilion), depending
on how the pavilion is cut. This cut is most frequently a square shape
where the length to width ratio is 1.0 to 1.1.
The princess cut tends to be the smallest of the shapes for the same
carat weight since the cut is basically an upside-down pyramid with
most of the carat weight in the pavilion. Princess cut requires great
care when setting and needs to be protected to avoid chipping or cracking.
Oval
Ovals provide a bigger surface area than a round with the same carat
weight and therefore are an excellent option for shoppers looking
for a brilliance of the round but a bigger size for their dollar.
Usually oval cut has the standard 58 facet pattern. Look for even,
well rounded ends with a full body having an optimal length-to-width
ratio of 1.33-1.66.
Emerald
The emerald cut is not a brilliant cut, but is called a step cut.
Step cuts are comprised of larger facets which act like mirrors. Because
of the angle, size and shape of the facets, the emerald cut shows
less brilliance than the other brilliant cut diamonds.
However, the emerald cut stone reveals a classic beauty and elegance
not seen in other cuts. Because of the open and large facets, we recommend
a higher color and clarity than you might consider for a brilliant
cut stone because they are more likely to become visible at lower
grades.
Pear
The Pear Shaped Brilliant is a combination of a Round brilliant and
a Marquise cut.
The pear shape usually has the 58 facet brilliant pattern, but can
be cut with different numbers of pavilion mains of 8, 7, 6, or 4 facets.
In a pear, look for a well-shaped point and an even shaped opposite
end with a length-to-width ratio of 1.50-1.75.
Pear-shaped diamonds work great for pendants and drop earrings.
Heart
The heart shape is a brilliant cut and bears some similarity to the
pear shape, except that there is a cleft at the top.
It is important to look for a perfectly symmetrical appearance where
the lobes (top arches) are of even height and breadth, and the overall
shape is pleasing to the eye.
Marquise
The name "Marquise" came from a legend of the Marquise of Pompadour
that the Sun King wanted a Diamond to be polished into the shape of
the mouth of the Marquise!
The marquise is typically cut into 58 facet standard brilliant (33
crown, 25 pavilion), the same as the round brilliant. The crown cut
is sometimes modified in the marquise to form what is called a "French
Tip," where the bezel facet at the point of the stone is eliminated.
Marquise diamonds frequently display a bow tie, so try to find a stone
in which this is minimal or absent. The marquise has a very big surface
area for the carat weight so it's an excellent option if you want
a big, long look for fewer dollars.
Trillion
The trillion cut was developed in the late seventies.
The trillion is a triangle that has equilateral sides. It is a combination
cut of the step and the brilliant cut diamond and when cut correctly
has a wonderful brilliance. It is often cut shallow and often looks
large for its carat weight.
Trillion diamonds are beautiful when flanking a center diamond, or
in a more advant-guarde piece as a center diamond. A matched pair
also creates beautiful earrings.
Baguette
The baguette is a step cut style used frequently as a side stone.
Baguettes have unleveled corners, usually only two rows of facets,
and may be rectangular or tapered. Like the emerald cut, the baguette
does not have the sparkle of a brilliant cut but has a classic beauty.
Higher color and clarity are important because there are not facets
to hide inclusions or body color.
The color scale is used to evaluate a diamond's color tint, as well as playing
a significant role in determining its price. Colorless diamonds being the
most desirable of course. Color is best evaluated in natural light, as high
intensity artificial lighting can make the diamond appear to be of a better
color grade than it actually is. Diamonds should also be examined for fluorescence,
as blue photoluminescence will also make the diamond appear to be of a better
color grade.
GIA
Color Grades:
[ D-E-F ] Colorless> – Color tint undetectable
to unaided, trained eye even when compared to white standard.
[ G-H ] Near Colorless – Color tint almost undetectable
to the trained eye, but apparent when compared to white standard.
[ I-J ] Near Colorless – A trace of tint just detectable to
the trained eye, but noticeably apparent when compared to white standard.
[ K-M ] Faint Yellow to Faint Brown - Tint apparent to the
trained eye and readily apparent when compared to white standard.
[ N-R ] Very Light Yellow to Very Light Brown - Tint is easily
apparent to the unaided, trained eye.
[ S-Z ] Light Yellow to Light Brown - tint is obvious to the
unaided, trained eye.
Diamond prices
increase significantly as the color scale ascends towards colorless.
Clarity measures the relative visibility of external blemishes or internal
imperfections (inclusions) naturally occurring within a diamond as evaluated
by a qualified gemologist. The clarity scale (GIA) is divided into six primary
categories:
[
F or FL ] Flawless
No discernible surface blemishes or inclusions visible when viewed
at 10x magnification. [ IF ] Nearly Flawless
Insignificant surface blemishes and no internal defects visible at
10x magnification.
[VVS-1
& VVS-2] Very,Very Slight Inclusions
Extremely difficult to very difficult to find surface blemishes or
minute inclusions at 10x magnification, but can be more readily seen
at 10x once located at 20x magnification.
[
VS-1 & VS-2 ] Very Slight Inclusions
Difficult to somewhat easy to find surface blemishes or minor inclusions
at 10x magnification.
[
SI-1 & SI-2 ] Slight Inclusions
Easy to very easy to find surface blemishes or readily noticeable
inclusions at 10x magnification, but will usually appear to be "eye
clean" without magnification, though some stones will show slight
inclusions when viewed from the side against a white background (note:
GIA does not recognize an SI-3 clarity grade).
[
I-1 ] Imperfect
Surface blemishes or obvious inclusions are somewhat difficult to
find with the naked eye, but are easy to see especially after being
located with 10x.
[
I-2, I-3 ] Imperfect
Surface blemishes or obvious inclusions are somewhat easy, or very
easy to find with the naked eye. I-2 inclusions will have an effect
on either the diamond's aesthetic appearance (beauty) or durability
(potential for cracking), I-3 inclusions will have an effect on both.
Diamond prices increase dramatically as clarity category lines
are crossed. SI clarity is generally considered to be the best compromise
between cost and appearance, providing excellent value for stones of G-I
color and proper proportions (cut). Buyers should exercise caution when
making purchases from jewelry merchants who don't know or won't state the
clarity of the diamonds offered. Buyers should also be aware that due to
the use of smaller diamonds in jewelry pieces, these diamonds are less tightly
graded and broader clarity range (two grades, such as SI-1 to SI-2, or I-1
to I-2) specifications are therefore not uncommon.
Enhanced
Clarity - New laser techniques have made it possible to improve
diamond clarity. Laser treatment is used to make flaws less visible and
thus improve the stone aesthetically. The effects of the laser treatment
are permanent.
The weight of a diamond is generally given in carats. One carat equals 0.2
grams. The weight of small diamonds is frequently expressed in points. 100
points equals 1.00 carat.
As diamonds increase in weight, their size becomes less predictable. Diamonds
with a shallow cut can have a greater diameter than a deep cut with the
same weight. So if size is important to you, focus on diamond measurements
as opposed to carat weight. Diamonds that look big for their weight may
have reduced brilliance and fire. An increase in carat weight does not produce
the same increase in millimeter diameter. For example, there is a 25% increase
in carat weight from 1.00 carats to 1.25 carats but less than 8% increase
in diameter (6.5 to 7.0 mm).
Look for diamonds that have a diameter measurement that is at least as large
as the average for that carat weight. There is no need to pay for the carat
weight you can't see.
CHAMPAGNE
COLOR DIAMOND CLASSIFICATIONS
AS DEVELOPED BY THE INDO-ARGYLE CORPORATION
Stones rated "N" (very light yellow or brown) or lower are frequently
set in yellow gold settings and referred to as "Champagne" diamonds.
These create very unusual jewelry and are a welcome addition to the jewelry
industry. The latest hot craze, in colored diamonds is the HTHP (High
temperature, high pressure) treated diamonds, mostly in blue, green, yellow
(canary) and some pink. The treatment is permanent and is not detectable.
If you see colored diamonds offered as low prices, assume that they are
treated and not natural occurring.
