We are frequently asked about what fluorescence in a diamond is,
and how it affects pricing. Well, the
simple answer is not quite so simple.
About half of the world’s diamonds production has fluorescence that can
be observed under when illuminated with a long wave ultra violet light.
About 10% of the diamonds on the market have florescence
that is strong enough to make a noticeable difference between the stone's color
in incandescent light which is low in uv light. and in sunlight or fluorescent
light which are high in uv. When a diamond has fluorescence it is
classified in intensity as being faint, medium, strong or very strong. In almost all cases that fluorescence color
seen under UV light is blue in color. this
is highly important, as blue fluorescence negates or minimizes the appearance
of yellow.
If the diamond being considered for purchase is high
color, say a D to G colored gem, it tends to be lower in wholesale price due to
the presence of fluorescence. How much
lower that price depends primarily if it has a waxy or somewhat milky white
appearance due to the fluorescence.
If the stone is H to I in color fluorescence likely has
little or no impact on the gem’s price, again unless it exhibits that waxy
appearance.
As the stone’s color grade drops to the J to M in color
range the presence of blue fluorescence may have a beneficial impact on the
stone’s appearance of color, and may help the stone bring a higher retail
price.
When we are looking at loose, unmounted diamonds in our
office the stones are typically presented in a small folded envelope called a
flute. These diamond paper flutes are
lined with a blue colored paper liner, which makes the gems contained inside
appear whiter than they actually are.
Retail dealers usually show these loose gems on a blue or
dark colored felt pad, which also makes them, look whiter.
Ask to see the stone upside down on a folder piece of white
paper, with the white paper below and behind the gem. This is the best way to determine if a stone had body color and
if it is a darker or lighter hue that another gem place next to it on the
paper.
The Gem Guys
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