Diamond Certification
Since most consumers are not diamond experts, a certificate is an easy way to distinguish differences in diamonds.
A certificate is a grading report from an independent laboratory prepared by a certified Gemologist. The report commonly includes a plotted diagram of your diamond and information about the shape, color, carat weight, clarity, and cut. It gives the exact measurements, table and depth percentages, as well as grading the symmetry and polish of the diamond. It will also have information about fluorescence. A grading report should not include any statement of monetary value about your diamond. It is simply to assure you of the quality and authenticity.
When you purchase a diamond
from Americus Diamond, we can provide you with a laboratory
certificate from one of the top two labs: Gemological
Institute of America (GIA), or European Gemological
Laboratory USA (EGL). Americus Diamond understands
the importance of quality and value, which is why we only
use the most distinguished labs in the world.
Diamond Cut
The cut of a diamond refers to the angles and proportions
of the diamond. As light enters a diamond, a well-cut stone
will reflect the light from one facet to another and then
disperse and reflect it through the top of the diamond. A
diamond of good proportions will have more fire and
brilliance. A diamond that is too shallow or too deep will
loose light out of the bottom or sides of the stone
reducing the brilliance.
The shape and the size of a
diamond are easily seen while the differences in
proportions may be more difficult to spot, even though it
is the most important feature in determining the beauty of
the diamond. Some of the elements in determining a
diamond’s proportions are the table size, depth
percentages, crown angles, girdle thickness, polish, and
symmetry. Read below to learn more about some of these
characteristics.
The table size is the size of the table relative to the
diameter of the diamond. It is expressed as a percentage.
To grade the table percentage of a round diamond, divide
the longest table diameter by the average girdle diameter
and multiply the result by 100.
Americus Diamond Find Diamond Jewelry
To grade the table percentage of a fancy shape (anything
other than a round), divide the width of the table by the
width of the stone and multiply the result times a hundred.
Table diameters of fancy shapes are measured at the same
point as their widths.
The total depth percentage is
the depth from the table to the culet. It is expressed as a
percentage relative to the girdle diameter. Depth
percentage affects how the light will interact in the
diamond, and thus impacts its brilliance. To calculate the
depth percentage of a round brilliant diamond, divide the
depth of the diameter by the average girdle diameter and
multiply it by a 100. To figure the depth percentage of a
fancy shape, divide the depth by the width, and then
multiply by 100.
Brilliance in a diamond is also affected by the pavilion
depth percentage, which is the distance from the girdle
plane to the culet or point at the bottom of the diamond.
It is expressed as a percentage of the girdle diameter. The
depth can vary slightly because the table and crown size
also affect the brilliance of the diamond. Round diamonds
that have pavilion depths shallower than 38 percent often
have a reflection of the girdle under the table that looks
like a ring. This is known as a fisheye and often the stone
will look dull or flat. Fisheyes may also be found deeper
in the pavilion when the table percentage is larger than 67
percent. If the pavilion is deeper than 48 percent, the
stone will appear dark in the center, which is known as
nailheads.
Symmetry reefers to the cutter's skill in creating equality
between corresponding parts of a stone, which is important
in producing an equal display of fire, scintillation, and
brilliance. There are no perfectly symmetrical diamonds but
it is important that the diamond is round and the culet is
in the center of the diamond. Other examples of symmetry
variations include misaligned facets, off-center, table,
wavy girdles, and table not parallel to girdle.
Diamond Ideal Cut
The culet of a stone is the
facet at the bottom of a diamond. It is put there primarily
for protection. A culet will look like a small white spot
in the center of the table. If a diamond is cut without a
culet it will come to a point at the bottom, however, it
has little or no effect on the value of the stone.
For maximum scintillation, brilliance, and dispersion, good
polish is essential. Polish of a diamond refers to how well
the facets of the stone are polished during the cutting
process.
Diamond Color
Most diamonds in the world are yellow or brown, making a
colorless diamond very rare. Slight color differences in
diamonds of comparable weight and clarity will have
hundreds --even thousands -- of dollars difference in
price. Color differences are very subtle. For example, it
is difficult to see a difference between an E and F colored
diamond.
A colorless diamond may be more rare but not necessarily
more beautiful. Some people prefer a colorless diamond
while others prefer a faint yellow. It is important to see
the different colors of diamonds side-by-side when deciding
what color diamond you prefer. At Americus Diamond we carry
diamonds from icy white to a warmer yellow. Come visit our
store and let one of our sales professionals compare
diamond color and help you decide what color is right for
you.
Americus Diamond Color Scale
DEF Colorless – These look
great in a white metal
GHIJ Near colorless – Looks great in white metal
KLM Faint yellow – these look especially good in yellow
metal.
The Gemological Institute of America (GIA) created a
universal diamond color scale that grades white to yellow
diamonds. It begins at D (colorless) and runs to Z (light
yellow). Each letter grade represents a range of color, not
necessarily one specific color. Diamonds are graded loose
and color is graded with the diamond face down. Graders
compare the diamond to a master set of stones. They are
looking at the depth of the color, not the hue itself. It
is necessary to have a specific and consistent light source
when grading color.
What causes color in diamonds? A diamond's color depends on
the kinds of atoms it contains, their arrangement, and how
they are bonded together. A diamond of 100 percent pure
carbon atoms in a uniform isometric arrangement would be
colorless. However, most diamond crystals pick up some
other atoms in the growth process. When carbon atoms are
replaced by nitrogen atoms in the diamond crystal, the
stone will appear yellow. When boron atoms replace carbon
atoms, we see the diamond as blue. Experts are not sure
what causes diamonds to be brown, pink, or red. When there
is radiation present, structural changes will color a
diamond green. Other colors are caused by structural
distortion and chemical impurities. The rarest fancy color
is purple followed by red and green.
Americus Diamond Jewelry Clarity
The clarity of a diamond refers to the presence of
inclusions or blemishes and range on a scale from Flawless
to Imperfect. Inclusions are natural identifying
characteristics such as minerals or fractures, appearing
while diamonds are being formed. They may look like clouds,
feathers, or tiny crystals. Blemishes are external and can
look like scratches and are part of the rough crystal
surface left on the finished stone. The general term for
blemishes and inclusions is clarity characteristic. These
characteristics seldom affect the strength or durability of
the diamond, only the rarity.
Below are some descriptions of a few clarity
characteristics.
Graining is an irregularity in the atomic arrangement of a
growing crystal. It may look like faint lines sometimes in
a group or parallel. It may also look like a hazy area in
the stone.
Included crystals are crystals of other minerals and occur
in groups or singly. They can be any size but small ones
are called pinpoints. Included crystals that reach the
surface are called knots.
A natural is a spot on the crystal's original surface that
the cutter left exposed. Many diamonds have naturals. These
are plotted on a laboratory certificate usually with green
and sometimes black marks.
To view inclusions, jewelers use 10x power magnification.
Americus Diamond has several microscope areas through which
customers can view their diamonds and identify the
imperfections. Every diamond will have identifying
characteristics that are unique to that particular stone.
Flawless diamonds show no inclusions or blemishes of any
kind when graded under 10x magnifications.
Clarity Scale
* Internally Flawless diamonds (F-IF) have no inclusions
but do have minor surface blemishes.
* VVS1 and VVS2 are diamonds which contain minute
inclusions that are difficult even for a skilled grader to
see under 10x magnification.
* VS1 and VS2 are grades where inclusions are clearly
visible under 10x magnification but are still characterized
as small. For example, you may see a small cloud or several
pinpoints.
* SI1 and SI2 are diamond grades that are fairly noticeable
or easy to see under a 10x magnification. Typical
characteristics include clouds, knots, pits and feathers.
Usually these are not visible to the unaided eye.
* I1, I2, and I3 are diamond grades which have inclusions
that are obvious under 10x magnification as well as visible
to the unaided eye
The clarity
of a diamond refers to the presence of inclusions or
blemishes and range on a scale from Flawless to Imperfect.
Inclusions are natural identifying characteristics such as
minerals or fractures, appearing while diamonds are being
formed. They may look like clouds, feathers, or tiny
crystals. Blemishes are external and can look like
scratches and are part of the rough crystal surface left on
the finished stone. The general term for blemishes and
inclusions is clarity characteristic. These characteristics
seldom affect the strength or durability of the diamond,
only the rarity.
Below are some descriptions of a few clarity
characteristics.
Graining
is an
irregularity in the atomic arrangement of a growing
crystal. It may look like faint lines sometimes in a group
or parallel. It may also look like a hazy area in the
stone.
Included
crystals are crystals of other
minerals and occur in groups or singly. They can be any
size but small ones are called pinpoints. Included crystals
that reach the surface are called knots.
A
natural is a spot on the crystal's
original surface that the cutter left exposed. Many
diamonds have naturals. These are plotted on a laboratory
certificate usually with green and sometimes black marks.
To view inclusions, jewelers use 10x power magnification.
Americus Diamond has several microscope areas through which
customers can view their diamonds and identify the
imperfections. Every diamond will have identifying
characteristics that are unique to that particular stone.
Flawless diamonds show no inclusions or blemishes of any
kind when graded under 10x magnifications.
- Internally Flawless diamonds (F-IF) have no inclusions but do have minor surface blemishes.
- VVS1 and VVS2 are diamonds which contain minute inclusions that are difficult even for a skilled grader to see under 10x magnification.
- VS1 and VS2 are grades where inclusions are clearly visible under 10x magnification but are still characterized as small. For example, you may see a small cloud or several pinpoints.
- SI1 and SI2 are diamond grades that are fairly noticeable or easy to see under a 10x magnification. Typical characteristics include clouds, knots, pits and feathers. Usually these are not visible to the unaided eye.
- I1, I2, and I3 are diamond grades which have inclusions that are obvious under 10x magnification as well as visible to the unaided eye