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Gemesis Cultured Diamonds
Cut, Color, Carat,
and Clarity (c-4's)
Cut and shape have taken on the same
meaning when discussing diamonds... this is not strictly correct.
There are many different shape diamonds but really just two
cuts... brilliant cut and step cut.
Shapes with step cut:
Emerald, Asscher, Baguette, Trapezoid.
Shapes with brilliant cut:
Round, Oval, Pear, Marquise, Princess, Radiant, Cushion,
Heart.
Selecting a particular shape is a personal choice... Cut properly
each one has its own distinct charm and beauty and will retain
it's value.
The brilliance and beauty lies ultimately in the hands of the
cutter. The temptation to cut a diamond for heavier weight [rather
than for elegance and brilliance] is the dilemma facing all
manufacturers.
To produce beautiful diamonds the cutter must elect to apply the
best proportion criteria and demand precise faceting and polishing
from skilled craftsmen.
When cut correctly a diamond draws light into the stone from the
top only, and will reflect a brilliance nothing else in nature can
equal. Cut imperfectly, the light is not captured or reflected
efficiently... resulting in less brilliance and lower value.
Q:
Why are all diamonds not cut perfectly?
A: The market-place is driven by weight and
cutters have financial incentive to produce heavier rather than
more perfectly cut diamonds.
Work with a trusted expert who can illustrate and explain the
finer points of cut and polish.
Understanding
Colored Diamonds
Diamonds with color relate to white
diamonds as a Ferrari does to a BMW – very rare, costly and not for
everyone.
More rare than white diamonds, natural colored diamonds exist in a
rainbow of colors and intensities. Less than one percent of the
thousands of diamonds graded annually by the GIA
qualify as "natural fancy colors."
With colored diamonds the familiar "four C's" (color, clarity, cut
and carat size) must be re-aligned to establish value. Unlike
whites... valued for their absence of color, "fancy colors" are
desired precisely because of their color.
Whites diamonds are classified on a D to Z color scale, with D being
whitest and Z denoting a yellow color. When the yellow color goes
beyond 'Z' the diamond qualifies as a "fancy yellow"
Color 'intensity' is described by the GIA as
follows:
[In ascending order of rarity and value]
faint
very light
light
fancy light
fancy
fancy intense
fancy vivid
fancy deep
In addition to color intensity the GIA will attempt
to describe the color... there are infinite possibilities.
Examples:
orangish yellowish pink
greenish yellow
purplish pink
pink
yellow
blue
gray blue
bluish gray
brownish orangish pink
yellow brown
etc. etc.
Often called "canary diamonds" yellow diamonds are more reasonably
priced than pinks, blues, greens, purples and reds. The more exotic
colors are extremely rare and costly.
The different colors are caused by the presence of various trace
elements... yellow is due to the presence of nitrogen in the atomic
structure, blue is produced by boron, green as a result of naturally
caused radiation in the earth, pinks have traces of titanium
and many other colors are not fully understood.
When cutting colored diamonds the priority is to achieve deep, even
color distribution and you might observe different facet lengths and
angles when compared to whites.
Clarity in a fancy colored diamond is relevant but secondary to the
color characteristics. The GIA will certify "color
only" for a fancy color [if asked to do so] and make no comment on
clarity.
When selecting a fancy colored diamond remember each gem is
unique... many of the less intense colors have a wonderful charm and
a stone should be selected because it speaks to you rather
than because of details on any certificate.
Fluorescence
Blue fluorescence, the impact on color
and value ...
If a diamond reflects a bluish glow when excited with UV light the
stone is considered "fluorescent blue." The intensity of
fluorescence is described by the GIA as follows:
None [NN]; Faint [FT]; Medium [MED]; Strong [STB]; and Very Strong [VSB].
Faint and medium fluorescence are typically not detectable to the
naked eye and may be viewed simply as a characteristic of
any diamond.
Faint fluorescence does not influence value while medium
fluorescence in colors H and higher should be discounted a couple of
percent; however, when considering 'I' color or
lower, faint or medium blue fluorescence actually enhances the
color and makes these diamonds a few percentage points more valuable
than equivalent colors without fluorescence.
"Strong" and "Very Strong" blue fluorescence can often be detected
with the naked eye and can cause a diamond to appear less brilliant
and even milky. As a general rule these stones should be avoided.
In rare instances "strong blue" fluorescence may have a
minimal effect on brilliance; however, the mere presence of STB or VSB
on a certificate will lower the value by as little as 10% (if the
stone remains bright) and as much as 90% (if the diamond has
a "milky" appearance).
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