Grading Color
Although color grading for diamonds has existed since ages, the turn of 19th century has seen more standardization in the color gradation process of diamonds. The diamond color grade standards set by the following two organizations are well revered and recognized in the industry.
1. Gemological Institute of America (GIA)
2. American Gemological Society (AGS)
3. International Gemological Institute (IGI)
Grades diamonds' color on a numeric scale of 0 to 10.
GIA's alphabet grade has a universal appeal. The scale begins with the highest rating of D for colorless, and travels down the alphabet to grade diamonds with traces of very faint yellowish or brownish hue. The AGS Color Grade indicates where a diamond's color falls on a numeric scale that runs from 0 (colorless) to 10 (light yellow or light brown) in 0.5 increments.
Contrary to how it sounds, diamond color is determined by the absence of color. The less color present in the diamond the more color is returned. Perhaps the easiest way to imagine this is to envision the triangular prism we looked at in science class. When the prism was put in sunlight, a rainbow of color was displayed. Likewise, a colorless diamond will flash a dazzling spectrum of color.
The highest color grade for a diamond is “D”. “D” color diamonds are very rare and not commonly found in traditional jewelry. Most diamonds used in jewelry have a slight presence of color.
It is possible for diamonds to have a very high concentration of desirable color. These diamonds are known as Fancy and can be found in a wide variety of colors including yellow, green, pink, blue and the rarest of all, red.
Diamond color rating is the one aspect of diamond grading that is done exclusively with the naked eye. Using a sterile colorless light box, gemologists grade the color of a diamond by comparing the stone to other stones in a master set of diamonds of known qualities.
The highest color grade for a diamond is “D”. “D” color diamonds are very rare and not commonly found in traditional jewelry. Most diamonds used in jewelry have a slight presence of color.
Diamond Fluorescence
Fluorescence is defined as a diamond's tendency to emit a soft colored glow when exposed to long-wave ultraviolet light (such as the lighting frequently seen in dance clubs) or fluorescent light (such as the lighting frequently seen in a showroom). Most fluoro diamonds fluoresce a blue glow which gives a whiter appearance to the diamond similar to the bluing liquid that makes white laundry even whiter. In very rare cases though, strong fluorescence in a high color grade diamond may make the diamond appear foggy or oily. Fluorescence in lower color grade diamonds enhances the appearance of the diamond making the stone a great value-for-money purchase.
Fluorescence is a complex phenomenon that is more debated than understood. Consumer attitude over fluorescence varies. While some people are prejudiced against fluorescence, many actually enjoy the effect. It is a matter of what appeals to the aesthetics. And the fact fluoro diamonds may cost less is a real bonus.
