When jewelers speak of a diamond's color, they are usually referring to the presence or absence of
color in white diamonds. Color is a result of the composition of the diamond, and it never changes over time. Because a colorless diamond, like a clear
window, allows more light to pass through it than a colored diamond, colorless diamonds emit more sparkle and fire. The formation process of a diamond
ensures that only a few, rare diamonds are truly colorless. Thus the whiter a diamond's color, the greater its value.
[NOTE: Fancy color diamonds do not follow this rule. These diamonds, which are very rare and very expensive, can be any color from
blue to green to bright yellow. They are actually more valuable for their color.]
To grade 'whiteness' or colorlessness, most jewelers refer to GIA's professional color scale that begins with the highest rating
of D for colorless, and travels down the alphabet to grade stones with traces of very faint or light yellowish or brownish color. The color scale
continues all the way to Z.
Some people seek diamonds that produce this unique effect, while others avoid it. The visible effects of fluorescence grades of
faint, inert, negligible, and medium, can only be detected by a trained gemologist with specific UV light. A fluorescence grade of strong or very strong
can make a diamond with a near-colorless grade look even whiter. In some very rare instances a diamond with very strong fluorescence can give the
diamond a slight hazy or oily appearance. Diamonds with a strong or very strong fluorescence are a better value for the end customer because the market
prices them slightly lower than diamonds with faint or negligible fluorescence.
WHAT COLOUR GRADE IS THE BEST ?
For the purist, look for a colorless diamond with a grade of D-F and a fluorescence rating of faint, inert, none, or negligible.
For an excellent value in a diamond with no noticeable color to the unaided eye, look for a near-colorless grade of G-I, and a
fluorescence grade of medium or strong blue.
Or, if you'd rather not compromise on color but would like to stay on budget, choose a diamond with a good cut, SI1–SI2 clarity,
and consider going with a strong fluorescence. It will still be beautiful to the unaided eye and you may prefer the unique effect of a strong