Product Code Database
A chemically pure and structurally perfect diamond is perfectly transparent with no hue, or color. However, in reality almost no gem-sized natural diamonds are absolutely perfect. The color of a diamond may be affected by chemical impurities and/or structural defects in the crystal lattice. Depending on the hue and intensity of a diamond's coloration, a diamond's color can either detract from or enhance its value. For example, most colorless (white) diamonds are discounted in price when more yellow hue is detectable, while intense or (such as the Hope Diamond) can be dramatically more valuable. Of all colored diamonds, are the rarest. The Aurora Pyramid of Hope displays a spectacular array of naturally colored diamonds, including red diamonds.
As the diamond trade developed, early diamond grades were introduced. Without any co-operative development, these early grading systems lacked standard nomenclature and consistency. Some early grading scales were; I, II, III; A, AA, AAA; A, B, C. Numerous terms developed to describe diamonds of particular colors: golconda, river, jagers, cape, blue white, fine white, gem blue, brown, etc.
Pink and red are caused by plastic deformation of the crystal lattice from temperature and pressure. Black diamonds are caused by microscopic black or gray inclusions of other materials such as graphite or and/or microscopic fractures. Opaque or opalescence white diamonds are also caused by microscopic inclusions. Purple diamonds are caused by a combination of crystal lattice distortion and high hydrogen content.
Diamond color is graded by comparing a sample stone to a master stone set of diamonds. Each master stone is known to exhibit the very least amount of body color that a diamond in that color grade may exhibit. A trained diamond grader compares a diamond of unknown grade against the series of master stones, assessing where in the range of color the diamond resides. This process occurs in a lighting box, fitted with daylight equivalent lamps. Accurate color grading can only be performed with diamond unset, as the comparison with master stones is done with diamond placed on its table facet and pavilion side facing upwards ( i.e. "upside down"— resting on the face one normally looks at). When color grading is done in the mounting, the grade is expressed as an estimated color grade and commonly as a range of color. Grading mounted diamonds involves holding the mounted diamonds table close to the table facet of the master stone and visually comparing the diamond color under the same color conditions as unmounted diamond grading. The resulting grade is typically less accurate, and is therefore expressed as a range of color. While a grading laboratory will possess a complete set of master stones representing every color grade, the independent grader working in a retail environment works with a smaller subset of master stones that covers only the typical grade range of color they expect to encounter while grading. A common subset of master stones would consist of five diamonds in two grade increments, such as an E, G, I, K, and M. The intermediate grades are assessed by the graders judgement.
Diamonds in the normal color range are graded loose (for example F–G).
| + Diamond color grading scales Organizations: GIA – Gemological Institute of America, AGI – Antwerpse Gemologische Instelling, AGS – American Gem Society, CIBJO – Confédération International de la Bijouterie, Joaillerie, Orfèvrerie des Diamantes, Perles et Pierres (World Jewellery Confederation), IDC – International Diamond Council, Scan. D.N. – Scandinavian Diamond Nomenclature | |||||||||||||
| grade and description Diamond Grading: Lab Manual Gemological Institute of America, Carlsbad, 2004 | grade and electronic colorimeter scale | grade and electronic colorimeter scale The AGS Way: Diamond Grading Standards American Gem Society, 1999 | gradePagel-Thielsen, Verena G.G., F.G.A. Diamond Grading ABC: The Manual Rubin & Son n.v., Antwerp, 9th edition, 2001, . | grade and description | grade for .50ct and over Engagement Diamond FAQ | grade for under .50ct | series 1 scale | series 2 scale | |||||
| D | Colorless | 0 | 0–0.49 | 0 | 0–0.75 | Exceptional white + | Exceptional white + | Colorless | River | White | Finest White | Jager | |
| E | 0.5 | 0.5–0.99 | Exceptional white | Exceptional white | River | ||||||||
| 1 | 0.76–1.35 | ||||||||||||
| F | 1.0 | 1.0–1.49 | Rare white + | Rare white + | Colorless when viewed through the crown | Top Wesselton | Fine White | ||||||
| 2 | 1.36–2.00 | ||||||||||||
| G | Near Colorless | 1.5 | 1.5–1.99 | Rare white | Rare white | Top Wesselton | |||||||
| H | 2.0 | 2.0–2.49 | 3 | 2.01–2.50 | White | White | Wesselton | White | Wesselton | ||||
| I | 2.5 | 2.5–2.99 | 4 | 2.51–3.0 | Slightly tinted white | Slightly tinted white | Slightly colored | Top Crystal | Slightly tinted white | Commercial White | Top Crystal | ||
| J | 3.0 | 3.0–3.49 | 5 | 3.01–3.75 | Crystal | Top silver cape | Crystal | ||||||
| K | Faint Yellow | 3.5 | 3.5–3.99 | Tinted white | Tinted white | Top cape | Tinted white | Top cape | |||||
| 6 | 3.76–4.5 | Silver cape | |||||||||||
| L | 4.0 | 4.0–4.49 | |||||||||||
| M | 4.5 | 4.5–4.99 | 7 | 4.51–5.50 | Tinted color 1 | Tinted color | Slightly colored to colored | Cape | Tinted color | Light cape | Cape | ||
| N | Very Light Yellow | 5.0 | 5.0–5.49 | Tinted color 2 | Low Cape | ||||||||
| O | 5.5 | 5.5–5.99 | 8 | 5.51–7.0 | Light yellow | Cape | Very light yellow | ||||||
| P | 6.0 | 6.0–6.49 | Light yellow | ||||||||||
| Q | 6.5 | 6.5–6.99 | |||||||||||
| R | 7.0 | 7.0–7.49 | 9 | 7.01–8.5 | |||||||||
| Dark cape | |||||||||||||
| S | Light Yellow | 7.5 | 7.5–7.99 | Tinted color 3 | Yellow | ||||||||
| T | 8.0 | 8.0–8.49 | |||||||||||
| U | 8.5 | 8.5–8.99 | 10 | 8.51–10 | |||||||||
| V | 9.0 | 9.0–9.49 | |||||||||||
| W | 9.5 | 9.5–9.99 | |||||||||||
| X | 10 | 10+ | 10+ | ||||||||||
| Y | |||||||||||||
| Z | |||||||||||||
Laboratories use a list of 27 color hues that span the full spectrum for colored gems and diamonds (Red, Orangish-Red, Reddish-Orange, Orange, Yellowish-Orange, Yellow-Orange, Orange-Yellow, Orangish-Yellow, Yellow, Greenish-Yellow, Green-Yellow, Yellow-Green, Yellowish-Green, Green, Bluish-Green, Blue-Green, Green-Blue, Greenish-Blue, Blue, Violetish-Blue, Bluish-Violet, Violet, Purple, Reddish-Purple, Red-Purple, Purple-Red, Purplish-Red). A modifying color combination can also be added (e.g., Olive or Brown-Olive) for stones without the purest hues. Additionally, for diamonds the following colors are used: White (which are milky), Black (which are opaque), Gray, Pink, Brown.
The saturation of these hues is then described with one of nine descriptors: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep, Fancy Vivid.
The terms "Champagne", "Cognac" and "Coffee" refer to different types of brown diamonds. In the diamond processing/dealing industry, the word "Brown" is considered a killer as far as diamond value goes. Even though champagne is a light yellow color, champagne diamonds are Light Brown. Cognac is usually used to describe a diamond that is Orangish-Brown because cognac is a deep golden-orange color. Coffee is usually used to describe a diamond that is a Deep Brown or Vivid Brown color. Some grading agencies may also describe brown stones as Fancy Yellowish-Brown, Fancy Light Brown, Fancy Intense Brown, etc.
Fancy diamonds are valued using different criteria than those used for regular diamonds. When the color is rare, the more intensely colored a diamond is, the more valuable it becomes. Another factor that affects the value of fancy-colored diamonds is fashion trends. For example, pink diamonds fetched higher prices after Jennifer Lopez received a pink diamond engagement ring.
Fancy-colored diamonds such as the deep-blue Hope Diamond are among the most valuable and sought-after diamonds in the world. In 2009, a blue diamond fetched the then highest price per carat ever paid for a diamond when it was sold at auction for 10.5 million Swiss francs (US$9.5 million at the time) which is in excess of US$1.3 million per carat. This record was broken in 2013 when an orange diamond sold for US$35 million or US$2.4 million per carat. It was again broken in 2016 when the Oppenheimer Blue, a vivid blue diamond became the most expensive jewel ever sold at an auction. It is the largest fancy vivid blue diamond classified by the Gemological Institute of America ever sold at auction; it sold at Christie's in Geneva in May 2016 for US$50.6 million. The record was broken again by the Pink Star diamond on April 3, 2017. The Pink Star was sold at an auction in Hong Kong for US$71.2 m (553 million Hong Kong dollars including fees) to Chow Tai Fook Enterprises.(GBP 34.7m; 56.83m Swiss franc).
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