Acting as a prism, a diamond can divide light into a spectrum of colors and reflect this light as colorful flashes called fire. 

Just as when looking through colored glass, color in a diamond will act as a filter and will diminish the spectrum of color emitted. 

As showed hereunder, the less color in a diamond, the more colorful the fire, and the higher the color grade.

A yellow tinge in a diamond will be even more apparent when set on white gold or platinum, but on the flip side, won’t show as much if set in yellow gold. 

Also, please take note that the bigger the diamond, the more the body color of the piece will show. 

The best way to see the color of a diamond is to put it table down in an angled piece of paper or anything that is very white and to look straight through the pavilion.

D color grade: 

D is the highest color grade attributed to a diamond, denoting that the stone is entirely colorless; as such, they are scarce and command the highest prices.

E color grade: 

The color difference between a D and an E graded stone is usually only visible to an expert gemologist using master stones as a comparison. However, E graded stones are slightly cheaper.

F color grade: 

The color difference between an E and an F is only visible to an expert gemologist using master stones as a comparison. F grades are the lowest and, therefore, the least expensive of the premium colors.

G color grade: 

G graded diamonds are nearly colorless, and a slight color difference only become perceptible when compared to diamonds of grades D or E. G stones appear colorless, especially once set and therefore offer excellent value for money.  

H color grade: 

H colored diamonds are near colorless diamonds that still appear white or colorless if they are not compared side by side with higher color graded stones. The H color is generally considered the watershed between colorless diamonds and slightly tinted diamonds. As a result, the H color is of great value for money and unsurprisingly a popular option. 

I color grade:

I colored diamonds are very slightly tinted diamonds; however, once set in jewelry, these stones may appear colorless. If you are looking to maximize your budget, then an I colored diamond offers excellent value for money.  

J color grade: 

J colored diamonds are very slightly tinted diamonds. However, once set in jewelry, especially in yellow gold, it is harder to see the slight yellow tint which the J grade produces. If you are looking to maximize your budget or if you have a preference for slightly yellow-tinted diamonds, then the J grade is a great option, offering fantastic value for money. 

K color grade: 

K colored diamonds are slightly tinted diamonds; however, once set in jewelry, especially in yellow gold, it is harder to see the slight yellow tint which the K grade produces. If you are looking to maximize your budget or have a preference for slightly yellow-tinted diamonds, then the K grade is a great option, offering excellent value for money. 

L to Z color grade: 

L to Z color grades will display a yellowish or brownish tinge that detracts from the beauty of the diamond. It is also to be noted that the color will act as a filter on the white light traveling through the piece: therefore, such quality grade pieces might display slightly less fire than their colorless or near-colorless counterparts.

Diamond fluorescence indicates that the diamond emits light when exposed to Ultraviolet light (long-wave radiation) or sunlight (which actually, as we know, contains UV light).

Diamonds exhibit fluorescence when small amounts of the element boron are present in the stone. 

Blue is the most common color of fluorescence, but other colors are also possible. 

The majority (more than 2/3rd) of diamonds don’t exhibit fluorescence. 

A “D” color diamond with robust fluorescence may display a “haze” or “cloudiness” that detracts from the overall luster of the stone. 

However, diamonds exhibiting fluorescence, especially those diamonds with lower colors like I or J, may seem whiter and give the appearance of being G-color or H-color diamonds or even better. 

Here is the trick. 

In the subtractive synthesis (here we are talking about pigments, like paint), two colors mixed will always give another color. 

In the additive synthesis though (colored light), the opposite colors will add up to one another, thus creating “complete” white/colorless light.

Please note here that the two different syntheses have different color wheels, the position of the colors being very different, and the result obtained by mixing them too! 

Since the diamond trade still undervalues diamonds with any fluorescence in the colorless color-grades (D through F), customers may obtain a diamond at a relative bargain when buying one with faint or even medium fluorescence. 

For an excellent value in a diamond with no noticeable color to the unaided eye, look for near-colorless grades of G-color through J-color, and a fluorescence grade of medium or strong blue.

Listed below are the abbreviations for describing the strength of fluorescence that should be noted when reading a diamond grading report: 

N, NO, NON – No Fluorescence 

F, FB, FT, FA – Faint or Faint Blue Fluorescence 

SL, SLB, SLT – Slight Fluorescence 

M, MO, ME, MD – Medium or Moderate Fluorescence 

S, ST, STB, STG – Strong Fluorescence 

E, EX, EXB, EF – Extreme Fluorescence 

This necklace and earrings are seen here in their entirety under normal lighting conditions (left) and the long-wave UV lamp (right). 

Quite often, diamonds in a range of fluorescent strengths and colors are placed next to inert diamonds, yet the piece maintains a uniform overall appearance under normal lighting conditions.

– 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 fluorescence.