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Fluorescence is a form of light that is produced when ultra violet
light enters a diamond. Most diamonds contain some degree of fluorescence,
which ranges from very slight to very strong. Some diamonds contain
little or no fluorescence which raises their value.
Sunlight and most forms of indoor light contain small amounts of
UV light. However, in most cases, the fluorescent light emitted
does not effect a diamond's appearance. Fluorescence is most evident
when a diamond placed under a UV lamp in a dark room. Under these
conditions, a diamond will appear to have a blue glow. Some diamonds
will appear to have a yellow or even a green glow. We suggest avoiding
diamonds with a green or yellow tint.
Fluorescence has little or no effect on the appearance of most diamonds,
and in diamonds with a color rating of J or lower, it may even enhance
appearance. The blue glow of the fluorescent light and the yellow
tint of the diamond tend to cancel each other out. However, diamonds
in the colorless to near colorless range (D to F) may be affected
by fluorescence. These diamonds may appear milky or oily due to
their fluorescence. When purchasing a colorless diamond, we recommend
selecting one with little or no fluorescence.
Remember, when determining an acceptable level of fluorescence,
be sure to base your choice on the diamond's color. A commonly accepted
rule of thumb tells us that:
- The higher (colorless) grades, D through F, will be adversely
effected by flourescence.
They will appear milky or oily.
- The middle grades, G through I, appear to have some tolerance
for fluorescence. Mild to moderate amounts of fluorescence can
be acceptable. However it is advisable to shy away from strong
fluorescence with these color grades. Personal taste in the appearance
of your diamond is suggested here.
- The lower grades, J through M, can actually have their appearance
improved by fluorescence. The blue of the fluorescent light, and
the yellow tint from the diamond will have a tendency to cancel
each other out, allowing the diamond to look whiter.