Never bought a diamond before? There are just a few things you need to
know in order to speak intelligently about these beautiful stones and help you when
purchasing one. There are four main criteria used to describe the quality of a diamond,
and they are generally referred  to as the
Four C's: Color, Clarity,
Cut, and Carat .One
might argue that the most important "C " of all is actually a "B",
Beauty. Although the independent gemological labs we use are renowned in the trade, the
most accurate and detailed description in the world is only a poor attempt to put into
words how beautiful a diamond can be. In addition to being familiar with the four C's it
is also important to make sure that the diamond you are purchasing has been certified by
one of the top independent gem laboratories. The two most widely trusted labs among
diamond professionals are the Gemological Institute of America (GIA) and the European
Gemology Laboratory (EGL). These reports will describe the four C's for you in minute
technical detail.
A diamond’s color is graded on an alphabetical scale from D-Z to describe how much
or how little color a diamond possesses. With very few exceptions, diamonds that are
graded as colorless are considered to be the most valuable. Truly colorless stones, graded
D, are extremely rare and very valuable.
D-F: Colorless, perfect or almost perfect color.
G-J: Near colorless, good to very good color. This diamond may “face up”
colorless when mounted.
K-M: Light but noticeable yellow or brown tint. May “face up” near colorless
when mounted, especially when mounted in yellow gold.
While many diamonds appear colorless, or white, they may actually have subtle yellow or
brown tones that can be detected when comparing diamonds side by side. Diamonds were
formed under intense heat and pressure, and traces of other elements may have been
incorporated into their atomic structure accounting for the variances in color. A single
change in color grade can significantly affect a diamond’s value. Although the
presence of color makes a diamond less rare and valuable, some diamonds come out of the
ground in vivid "fancy" colors--well-defined reds, blues, pinks, greens, and
bright yellows. These are highly prized and extremely rare.
Clarity is an indication of a diamond's purity. It is the term used to describe quite
literally the clearness or lack of flaws in a diamond. All diamonds have some, naturally
occurring marks in them, which may or may not be visible to the naked eye. These are known
as imperfections or inclusions. In all diamonds, except the most rare, tiny traces of
minerals, gasses, or other elements were trapped inside during the crystallization
process. These are called inclusions, but are more like birthmarks. They are called this
because they are “included” in the diamond! They may look like tiny crystals,
clouds, or feathers and they're what make each diamond different and unique. 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 and how visible the inclusions are. The fewer and smaller
the inclusions, the more rare and valuable the diamond. Less than 1% of all diamonds ever
found have had no inclusions and can be called internally flawless (IF).
The following are abbreviations for terms that are used world wide to describe the
clarity of a diamond:
IF,VVS1,VVS2: Internally flawless or near flawless. Impossible to extremely difficult
to find any inclusions, even under 10x magnification. IF is Internally Flawless, and VVS1
and VVS2 are “Very, very slightly included”.
VS1,VS2: 100% clean to the naked eye, and moderately difficult to very difficult to
find inclusions with 10x magnification. VS1 and VS2 are “Very slightly
included”.
SI1, SI2, SI3: Should be completely to almost completely clear to the naked eye (eye
clean) when viewed from the top. Fairly easy to find imperfections with 10x magnification.
SI diamonds are “Slightly included”.
I1, I2, I3: Borderline “eye clean” to fairly easy to find imperfections with
the naked eye. Very easy to find imperfections with 10x magnification. I1 through I3
diamonds are “Included”.
Diamond Cut
This is one of the most important of all characteristics, and among the hardest to
judge. All other factors being equal, a poorly cut diamond can be worth less than half the
value of a well “made” stone. 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 retain the maximum weight from rough stones. You will find
poorly cut diamonds such as overly long or fat Marquises, extremely deep Heart Shapes and
Emerald Cuts, and Ovals and Pear Shapes with big shoulders, or overly deep or out of shape
Rounds. 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 and near ideal cut stones command a
premium.
The way a diamond is cut will most certainly influence 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 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. Shown below is an
example of how a finely cut diamond will reflect light.
Symmetry, polish, and faceting are the most noticeable features of cut, but also
important are percentages for depth, height and angles. 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.
The standard unit of measure for diamonds and other gemstones is the carat. One carat
is equal to 1/5 of a gram, or 1/142 of an ounce. The carat is also referred to as
containing 100 “points”. Therefore, a 50-point diamond weighs ½ carat, a
25-point diamond weighs ¼ carat, and so on.
The price per carat of diamonds can at times increase exponentially with size, due to
the rarity of larger gemstones.
A one-carat diamond typically costs 3.5 to 4 times what an equivalent ½ carat costs,
and the same goes for subsequent increases in size.
|