Diamond Buying and the Four Cs, Part 2: Diamond Color


Summary
For most gem buyers, color is probably the most well known of the Four Cs of gem grading. However, diamond color grading can be confusing.

In this second of a 4-part series of articles, we’ll explain the GIA color grading scale and learn how fluorescence and metal settings can impact diamond colors. The Four Cs aren’t as distinct as they may seem, so we’ll also consider the combinations of color, clarity, cut, and carat to look for when diamond buying.

Reading time: 10 min 37 sec
diamond color - U to V color range stone
Light lemon-yellow diamond (color grade U-V, 2.02 cts, VVS2). © Diamonds by Lauren. Used with permission.
diamond color - Russian diamonds
Russian diamonds, approximately 0.7 to 0.9 mm, of different normal color grades. Photo by James St. John. Licensed under CC By 2.0.

The GIA Diamond Color Scale

The Gemological Institute of America (GIA) color scale for white or colorless diamonds ranges from grades D to Z. Any stone within that range falls within the “normal color range.”

diamond color - GIA diamond color chart
GIA color grades. Image by Open School of Diamond Gemology. Licensed under CC By 3.0.

The most highly valued diamonds have no color. Thus, the more color a stone has (yellow or brown), the lower the grade. Yellow or brown diamonds that make it past the Z grade, however, instantly go up in price. Such diamonds have enough color to be considered “fancy,” along with pink, green, and blue diamonds. (Once these diamonds have enough saturation to show these colors, they are automatically considered fancy).

As with other diamond grading scales, diamond value goes up exponentially with each increase in grade. (Conversely, value goes down exponentially as the color grade decreases). Whereas diamonds of any carat size hold value and find use, diamonds between L and V color grades appear less often in jewelry.

The GIA D-Z scale is divided into five categories:

  • Colorless — D, E, F.
  • Near Colorless — G, H, I, J.
  • Faint — K, L, M.
  • Very Light — N, O, P, Q, R.
  • Light — S, T, U, V, W, X, Y, Z.

White Diamonds

Of course, the most valuable diamond color is D. A diamond of this grade commands a premium simply because of its complete colorlessness.

diamond color - D color
0.92 carat, D color, internally flawless diamond with excellent cut grade. © MyDiamondZone. Used with permission.

You are probably familiar with the idea of diamonds being white. However, 98% of gem-quality diamonds actually contain some amount of yellow due to nitrogen impurities within the diamond.

diamond color chart
Diamond color chart, from colorless to faint yellow. Image by Open School of Diamond Gemology. Licensed under CC By 3.0.

Cape Diamonds

All faintly yellow diamonds (not colorless and not fancy yellow) are called “Cape diamonds.”  However, some jewelry lines will specifically market only stones of lower color grades, K to Z, as “Cape diamonds” in order to promote them as affordable alternatives to “non-Cape” diamonds.

diamond color - yellow and white gold diamond engagement ring
10K yellow and white gold engagement ring with 3 round main diamond stones (0.03 cts each, J color, I2 clarity) and baguette accent stones (0.14 cts, K color, I3 clarity). The diamonds, especially the baguettes, appear quite yellow against the band. K diamonds are in “Cape Diamond” territory. (If the metal around the main stones had been yellow instead of white gold, the K diamonds would have been shown to greater advantage). Photos © Midwest-Jewelry. Used with permission.

Lemonade Diamonds

Sometimes, vendors market W-Z color grade diamonds specifically as “lemonade” or near-fancy yellow diamonds.

Diamond Color Grades as Ranges

Consumers and vendors pay a great deal of attention to specific color grades when a stone sits on the high end of the scale. Once colors move past K, however, the grades are often given as ranges, such as U-V, W-X, and Y-Z.

diamond color - Y-Z color diamond engagement ring
The gold prongs enhance the yellow of this Y-Z diamond (1.51 cts, SI2), while the white setting enhances the whiteness of the engagement ring’s side stones. © Diamonds by Lauren. Used with permission.

Diamond Color Grades and Price Jumps

You’ll find an enormous price difference between a D and an E color diamond. The next biggest price difference lies between an F and a G color diamond. That’s understandable, as G falls into the “near colorless” rather than “colorless” category.

Just as diamonds have “magic number” carat sizes, they also have “magic letter” color grades. You can find great deals just below them. For example, G and H stones make great value choices. Although they’re not much darker than F, they’re much more affordable.

Stones with I, J, and K color are commercial quality. You’ll commonly see them in stores such as Costco or Walmart, but high-end stores can carry them, too.

The Effect of Gold Colors on Diamond Color

Stones in the I, J, and K range start to look faintly yellow or brown, especially in larger carat sizes. Jewelers can disguise these colors, however, by setting the gems in yellow or rose gold. The color of the metal can make lower grade stones look whiter in contrast.

diamond color - engagement ring with U-V color diamonds
A light yellow center diamond (color grade U-V, VSI clarity) set in yellow gold to enhance the color. The side stones, light brown diamonds (K color, VS clarity) set in rose gold, appear whiter in contrast. © Diamonds by Lauren. Used with permission.

Use White Gold Settings for High Diamond Color Stones

Interestingly enough, yellow or rose gold settings do the opposite for stones of higher color grades. For stones G and above, the reflections of yellow or rose gold colors make the diamonds look warmer in tone. Therefore, a high-color grade diamond, if set in yellow or rose gold, is wasted. This will make the diamond appear to have the same tone as a stone with a lower color grade.

  • For a yellow or rose gold setting, purchase a lower color grade stone.
  • For a white gold setting, purchase a higher color grade stone.
diamond color - W-X color range diamond engagement ring
A yellow gold engagement ring setting with vivid and intense yellow diamond melee makes this 0.05-ct cushion-cut W-X color stone look more yellow. © Diamonds by Lauren. Used with permission.

Settings with Multiple Gold Colors

Of course, jewelers have become very conscious of the effect of metal colors on gems. As a result, rings with shanks of one color and bridges or prongs of another have become increasingly popular. For example, someone who wants to enhance or preserve the white color of a stone can set it with a white gold bridge and prongs, while using yellow or rose gold for the shank. This way, stones will appear whiter, whether high or low-colored, due to the white gold base beneath the stone, while the darker yellow or rose gold color of the shank will make the stones appear even whiter in contrast.

diamond color - yellow and white gold engagement ring
The gold prongs enhance the yellow of this cushion-cut, fancy vivid yellow (2.13 cts, VS1) diamond ring, while the white setting enhances the whiteness of the side stones. © Diamonds by Lauren. Used with permission.

Buying Diamonds Below J Color

Before purchasing a diamond below J in color, keep in mind that the brown or yellow color will be fairly noticeable. Generally, buying diamonds below J isn’t advised.

Nevertheless, some people prefer the soft, mellow look of a faintly yellow diamond as opposed to the hard, icy brilliance of a white diamond. Perhaps for these consumers, the pale yellow color has pleasant associations, such as candlelight. If this describes you, you still shouldn’t pay too much for diamonds of this color, despite the positive vibes they give.

If you’re considering a diamond below I in color for budget reasons, fluorescence may be your friend.

The Aurora Butterfly of Peace diamond collection contains 240 natural, fancy colored diamonds, total weight 167 cts. Some of the stones are fluorescent. The collection is shown in daylight and under ultraviolet light. Photos by Abronsteinwiki. Licensed under CC By-SA 3.0. (Slide show created to highlight fluorescence).

Diamond Fluorescence

A third of all diamonds fluoresce, and 90% of fluorescent diamonds fluoresce blue. In diamonds with high color grades, especially D-F, strong fluorescence is undesirable since it can make them appear milky.

diamond color - blue fluorescence
A pile of diamonds, roughly 0.5 mm in diameter, some fluorescing blue. Photo by James St. John. Licensed under CC By 2.0.

Fluorescent diamonds with higher color grades cost 15% less than non-fluorescent diamonds. On the other hand, diamonds of I color and below actually increase slightly in price if fluorescent. Since blue is complementary to yellow, medium to strong blue fluorescence can cancel out some of the yellow color.

diamond color - Portuguese diamond
Most colorless diamonds will lose value if fluorescent. However, the octagonal-cut Portuguese Diamond actually gains value due to its uniquely intense fluorescence, combined with its large size (127.01 cts) and flawlessness. Fluorescence makes this diamond appear milky blue even under daylight. Photo by Observer31. Licensed under CC By 3.0.

This price boost is limited to blue fluorescence because, needless to say, yellow or green fluorescence will increase a stone’s yellow color. However, when a stone reaches the fancy color range, yellow fluorescence becomes desirable.

diamond color - yellow fluorescence
A pile of diamonds, roughly 1 to 1.5 mm in size, some fluorescing yellow. Photo by James St. John. Licensed under CC By 2.0.

Professional Diamond Color Grading

For the average consumer, differentiating diamonds with color G and above proves difficult. (Try it for yourself in this diamond color sorting quiz!) So, how do professional diamond graders tell the difference? They use a master set of diamonds. These include stones representing the lightest possible color for each diamond color grade.

Color Master Sets

When grading a diamond, professionals compare it with different stones in the master set. First, they identify the two master stones between which the test stone’s color lies. One is lighter than the test stone, the other darker. They then assign the test stone the color grade of the lighter master stone. For example, if a test diamond’s color lies between G and H, it’s a G color stone. (G is lighter than H. Remember that the master stone shows the lightest possible color for its grade. So, G has many slightly darker gradations before the color reaches H).

diamond color grader - Diamond Lite
Diamond Lite color grader. Photo by Open School of Diamond Gemology. Licensed under CC By 3.0.

Table Down or Table Up?

When evaluating diamonds in the normal color range, professionals place the stones table or face down. They do this because color looks more concentrated through the pavilion, and graders look for lack of color in these diamonds. In contrast, they grade fancy colored diamonds table or face up. In these stones, graders look for a maximum amount of color.

White Light and Neutral Colors

The master set diamonds sit in a white tray shaped like an angular trough that can rock backwards and forwards. The white tray itself sits in a gray light box that shines white light on the diamonds. Neutral colors are always used during diamond grading, because diamonds reflect the colors around them. Even wearing red, yellow, blue, or other bright colors while grading will throw off accuracy.

diamond color - master stones placed table down
Color grader with brilliant-cut comparison stones tables down. Photo by Open School of Diamond Gemology. Licensed under CC By 3.0.

Diamond Color and Recommendations for Other Diamond Qualities

  • Ideally, pair diamond colors of D, E, or F with clarity grades of F (flawless), IF, VVS1, or VVS2, especially if the diamond matches or exceeds one carat in size.
  • Diamond color of G, H, or I should be paired with VVS2, VS1, or VS2 clarity. Pair J, K, and L with SI1 or lower.
  • A stone smaller than one carat can have a color grade of I, J, or maybe even K without appearing too yellow.

Assessing Diamond Color Online

Just like clarity and cut, it’s essential to see the diamond’s color before you buy. Since color grades of colorless diamonds are based on body color, these grades can be misleading. What’s important is the face-up color, which you can only judge in accurate pictures or videos.

Both James Allen and Blue Nile provide close-up, 360° videos of the thousands of diamonds in their inventory. This lets you judge for yourself if any of the Four C’s is lacking.

Better yet, James Allen has hundreds of examples of different color diamonds in different ring settings. If you’re not sure whether the color will show, see what others have used in the same setting.

About the author
Phoebe Shang, GG
A gem lover and writer, Phoebe holds a graduate gemologist degree from the Gemological Institute of America and masters in writing from Columbia University. She got her start in gemology translating and editing Colored Stone and Mineral Highlights for a professor based in Shanghai. Whether in LA, Taipei, or New York, Phoebe spends her time searching for gems to design and being lost in good books.
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