2007年12月30日星期日
Diamonds Color & Fluorescence
Diamonds color is the presence or absence of color in white diamonds. Diamonds are graded on a color scale from D (most “colorless”) to Z (maximum amount of body color for “colorless” diamonds). Attention to tricks on color that are performed in order to deceive the buyer. Fluorescence: it is advisable to seek for faint blue fluorescence or none when choosing the diamond for the engagement ring. Color Speaking of diamonds color is referring to the presence or absence of color in white diamonds. With diamonds, the best color is no color. Diamonds are not all truly colorless, but the standard for judging all shades is the colorless/white diamond. The less color in a diamond, the more colorful the fire. Diamonds allow light to be reflected and dispersed as a rainbow of color. This light dispersion, or color flash, has no effect on the technical grading of color. The absolute finest colorless stone has a D rating, descending through each letter of the alphabet to Z, designating a diamond of light yellow, brown, or gray. Color in a diamond will act as a filter, and will diminish the spectrum of color emitted. If the color is more intense than Z, it is considered fancy. A fancy yellow diamond fetches a higher price than a light yellow diamond. Color is a result of the composition of the diamond, and it never changes over time. It may be caused by the presence of minute trace elements, such as nitrogen, within the atomic framework of the carbon crystal, scientifically measured in ppm (parts per million). As the body color becomes more intense, the grade for color descends the scale. The gradations are very precise. Discerning a single grade under less than ideal laboratory conditions is extremely difficult even for an expert. For accurate color grade it is always best to compare diamonds graded by either the GIA or the AGS. It would be advisable to select a diamond with at least a K color grade. It is also true that while most people strive to buy the most colorless diamond they can afford, there are many people who actually prefer the warmer glow of lower-color diamonds. Dazzling Black and White Diamond Jewelry From JewelryImpressions.com! Save Hundreds Now!! Grading Grading is performed in laboratories and only for diamonds which are unmounted — loose diamonds, and they do so under special light. Mounting can very much influence the perception of color. Even a trained professional cannot always tell the difference between, say a D color and an E or F color diamond on a mounted ring .
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