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know the following information.
All gemstones, including diamonds, have a weight which is
expressed in carats. One gram is equal to 5 carats. One carat is
divided into 100 "points" so that a diamond of 50 points is
described as a half carat in size, or 0.50 carat. Size is one of the
factors in determining the value of the diamond, but other factors
such as cut, clarity and color will also effect the final price.
Depending on how a stone was cut, it can look larger or smaller
than a stone of equal weight (see cut).
Because of their unique optical properties, diamonds, more than
any other gemstone, are capable of producing the maximum
amount of brilliance. While minute crystals of diamond or other
minerals are contained in almost all diamonds, a diamond that is
virtually free of inclusions and surface markings will be judged as
flawless. In these diamonds, nothing interferes with the passage
of light or spoils the beauty. But these diamonds are extremely
rare and will command a high price. To determine a diamond's
clarity grading, it must be examined under a 10x magnification by
a trained, skilled eye. Without magnification, you may never see
these inclusions. However, the fewer there are, the rarer your
diamond will be.
The most prized diamonds are colorless diamonds, because their
beauty depends entirely upon their remarkable optical properties.
In such diamonds, all the colors of the rainbow are reflected back
to your eye. While the majority of gem diamonds appear to be
colorless, others can contain increasing shades of yellow to
brown, some of which are referred to as champagne diamonds.
Other diamonds of exceptional color-blue, green, pink, and
amber--are known as "Fancy Colored". The color grading scale
varies from totally colorless to light color or tinted. The difference
between one grade and its neighbor is very subtle. Experts never
try to remember color; they use master diamonds of known color
for comparison.
you select is a matter of individual taste, and today your choice is
only limited by the skill and imagination of the craftsman. It is their
effort during every stage of the fashioning process that reflects
the maximum amount of light back to the eye. Most round,
brilliant-cut or fancy-shaped diamonds possess 58 carefully
angled flat surfaces, called facets, whose placement will affect
the fire, brilliance and ultimate beauty of your diamond. The cut of
a diamond is in direct conjunction to the proportion of a diamond.
With proper cutting (diagram1) the light passes through the top,
reflects off the sides, and then travels back out through the top,
giving the diamond optimum brilliance and dispersion. If the
diamond is cut too shallow (diagram2), light passes through the
bottom of the diamond. If the diamond is cut too deep (diagram3),
light passes through the side of the diamond, in both cases
inhibiting maximum brilliance and dispersion.
One of the fascinating conversations I have with many consumers is about a
diamonds fluorescence (or lack of). This is a natural phenomenon found in
approximately 35 percent of diamonds on the market today. Under long wave UV
light the diamond may fluoresce a color; blue, yellow, orange, green, and many
other subtle hues. It is in your best interest to stay away from any diamond that
fluoresces any color other than blue. Why would you buy a colorless diamond to
have it fluoresce yellow? Even some diamonds exhibiting strong blue
fluorescence can have a poor effect if it becomes too strong. Should the
florescence becomes to intense it can make your diamond look milky or dull in
bright sun light. Diamonds exhibiting this intensity would be termed overblue
(trade term). This is a very rare diamond indeed, but to make sure you’re not
buying an overblue diamond it would be a wise choice to purchase diamonds
with no more than medium fluorescence unless your jeweler can confirm that it
isn't an overblue.
What can a little fluorescence do for your diamond? Many believe that an H or I
color diamond can actually appear whiter (more colorless) than it is because of
this effect. Many years ago jewelers would refer to colorless diamond that had
blue fluorescence as a blue-white diamond.
Grading of Diamonds
The AGS report will give you all of the information that the GIA report does, it
also reports the necessary angles and dimensions to give the diamond a cut
grade by their standard. The AGS Diamond Quality Document reports the angles
and percentages using a diagram of a diamond. This makes the cut information a
little easier to relate to and understand which area of the diamond they are
referring to.
Either an AGS report or a GIA report accompanied with a Sarin report can give
you most of the information you need to make your purchase.
Use this information along with a trusted jeweler. Your jeweler should be able
to add information about optical symmetry, answer questions, explain the
reports in detail, and allow you to compare actual diamonds.
This will certainly lead you into making a informed diamond purchase. The GIA
report will include valuable information on many qualities of the diamond. It will
not include any cut grade. There is not enough information to know about the
cut grade from a GIA report. In all fairness GIA hasn't set a standard for cut
grade at this time. GIA is currently working on a cut standard for their lab.
To find the AGS cut grade of a diamond graded by GIA's lab you must also have a
Sarin report (or OGI) on the diamond. A Sarin (or OGI) is a computer that will
generate a report showing all of the necessary angles and dimensions to give a
round diamond a cut grade by the AGS standard (the only standard on round
diamonds at this time). A Sarin or OGI report can be a letter size piece of paper,
or simply a mailing label with all the necessary cut information.
Most respected grading reports do not place any value on the diamond. They
instead give an independent expert opinion on its quality. The most respected
labs, like the GIA and AGS, are recognized worldwide and are considered to be
stricter in their grading. Diamonds with either of these reports do trade for a
few percent more than diamonds without a report, or reports other than the GIA
or AGS.
