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Monday 9th September 2019

Decoding Colors: Orange

Diamonds, animals, plants, in fact, all objects, don't actually have a color, they give off light that appears to be a color. The color of a diamond is not an intrinsic property but an inherent property produced by the selective absorption and reflection of wavelengths of light transmitted through the diamond. Several external factors, combined with human perception and memory, have to be taken into account when naming the color of natural fancy diamonds. So let’s not mince words; no grading system can completely describe how someone perceives the color of a captivating fancy color diamond and terminology and accurate communication about color remains a fairly permanent challenge for the industry.

Fancy colors

"The FTC provides no guidelines for the use of the term “fancy-color” in the US, but there is general agreement in the international trade that fancy-color diamonds are either yellow or brown diamonds that have more color than a Z masterstone or they exhibit a color other than yellow or brown"
GIA

Several color spaces (RGB, CMYK, Pantone, RAL, Munsell…) define colors numerically by coordinates but Munsell, an American painter and art instructor, was the first to separate HUE —the specific spectral location of a given sensation of color, value or TONE —describing the lightness or darkness of a color, and chroma or SATURATION —referring to a color’s purity, into perceptually uniform and independent dimensions, and to illustrate the colors systematically in three-dimensional space. Thus Munsell’s well-documented model of the color order system was elected in 1995 as the basis to enhance the GIA’s International Diamond Grading System™.  

Color Space - Munsell. Encyclopedia Britannica.

The saturations steps on the horizontal axis vary with each hue & tone

The development of the grading method resulted in a system with 27 different hues and multiple terms to describe every tone and saturation from faint to deep and today this methodology is still the preferred reference in the industry.

Continuous Hue Circle - GIA

Continuous Hue Chart - Picture Courtesy © GIA 

Nevertheless, as is the case with every system, it has its limitations and, as stressed by John King who is widely recognized as the father of the new GIA grading system, “If a diamond is located near the boundary of its grade range, subtle differences between it and another diamond in one or more of these attributes can result in different grades.”  Further details about this science and art of grading natural fancy color diamonds can be found in our Encyclopedia.

Orange

"Orange is red brought nearer to humanity by yellow"
Wassily Kandinsky
The color orange radiates warmth and happiness and in some cultures, it’s considered a sacred hue, while in others it’s a symbol of royalty.  Pure vibrant orange diamonds are extremely rare and amongst the most mysterious of all diamonds. Why? Because orange is not a primary color and in order to be named a “fancy orange diamond“ stones need to have a perfect blend of red and yellow, with no secondary hue, and no traces of brown.
Origin of Color
"Orange bodycolor in diamond is usually caused by an absorption band centered at approximately 480 nm or by a high concentration of isolated nitrogen."
Wuyi Wang and Ren Lu  - GIA

Theoretically only pure diamonds with no crystallographic defects should be transparent and colorless. Yet, colors are always due to some impurity or defect in a diamond’s structure. The color orange is most likely the result of a combination of atoms of nitrogen present in the crystal and structural deformities.

When a diamond is formed and nitrogen atoms are present in the crystal, they are randomly dispersed throughout the lattice (Type Ib). Those color centres will induce some absorptions in visible light and cause the orange color. With heat and pressure some nitrogen can rearrange themselves and form aggregates (Type Ia) that will induce some other absorptions of the incident white light. Each structure will affect the way blue and yellow spectrum light are absorbed and produce a unique orange hue. Besides type Ib and type Ia some orange diamonds  type IIa (without nitrogen) have also been spotted. 

According to some scientists, other impurities - like hydrogen- could also interfere in the orange color formation. Yet, orange diamonds have still not yielded all of their secrets and remain a mystery that certainly explains their growing appeal.

Terminology - What's in a Name

Christened “Fire diamonds” by gemologist E. Streeter in his book ‘The Great Diamonds of the World’ (1882), orange diamonds will often have red or yellow modifiers. Brown and pink modifiers are also frequent and may result in stunning variation of orange from bright pumpkin orange to apricot, saffron, salmon, amber, toffee or cognac hues.

  • Orange hues vary from orangy yellow to orangy pink (red).

  • Modifiers can be brown, yellow, green, red and pink.

  • A pure orange diamond has no traces of brown and is neither dull nor deep.

  • A  pure orange diamond can be Faint / Light / Fancy/ Intense / Vivid / Deep

GIA’s hue and saturation levels are::

          

Source:GIA's Colored Diamonds Color Reference Charts. Picture Courtesy: GIA

 

Regarding the saturation of the color and according to the GIA “ Yellow-orange diamonds occur in a wide tone range and reach their strongest saturation at a slightly darker tone than do yellow diamonds. Diamonds in the orangy red hue do not typically reach as high saturation level as those in yellow, orange-yellow, or yellow-orange.”

 

 

3.40 ct Fancy Intense pinkish orange.

 

GIAPicture: GIA Colored Diamonds with Unusual Characteristics. Courtesy of Laurence Graff

 

4.15 ct Fancy Vivid pinkish orange. 

GIA. Picture courtesy: GIA Gems & Gemology - Wuyi Wang, Intensely colored Type IIa diamonds with substantial nitrogen related defects, vol. 39. Spring 2003.

 

 

Three Fancy Vivid yellow-orange.

These three diamonds (between 1.03 & 2.80ct) are in the same hue range and of approximately the same saturation. The differences in appearance are due to variations in tone, all of which are within the range that would be described in GIA’s colored diamond color grading system as Fancy Vivid yellow-orange GIA. 

Picture: Gems and Gemmology. Courtesy of Elisabeth Schrader.

 

  

It should be noted that some stones could be graded "fancy yellow orange" (orange with a yellow modifier) by one laboratory and "fancy orange yellow" (yellow with an orange modifier) by another laboratory but what’s in a name. 

 

Langerman diamonds. Decoding Colors by ydcdl 0.46 ct Fancy_Intense Yellow_Orange (graded by GIA)   

Fancy Intense Yellow Orange (graded by GIA)

Fancy Intense Orange Yellow (graded by GIA)

 

Fancy Vivid Orange Yellow (graded by GIA)

 

Main Sources

They are predominantly sourced from South Africa, Democratic Republic of Congo and Russia 

 

Fancy Vivid Yellowish Orange (graded by GIA) 

 

Exceptional Orange Diamonds 

Famous Orange Stones

  • In 2010, a 7.53 ct Fancy Vivid orange diamond was yielded by Namakwa diamonds in South Africa.  

  • The Koi diamond, a non conventional +32 ct orange diamond. Recovered in Congo, it’s a unique diamond regarding its color with orange, white yellow, black, and dark blue colors. 

 

Famous Auctioned Diamonds

  • In 1997 the “Pumpkin Diamond”, a 5.54 ct  Fancy Vivid orange, mined in Central African Republic fetched $1.3 million at Sotheby’s. Acquired by R. Winston and resold privately a few years after. 

  • In 2011 a 4.19 ct Fancy Vivid orange diamond was sold for $2.95 million. 

Picture Courtesy: Sotheby's

 

  • In 2013, “the Orange", a 14.82-carat, VS1, Fancy Vivid orange diamond was sold for $ 35,540,612 by Christie’s Geneva - an absolute record price per carat: $2.39 million.

Getty Image . The orange

Picture Courtesy: Getty Image

Famous Jewelry  

  • Queen Maxima from the Netherlands received as an  engagement ring a superb oval orange diamond, especially befitting as the country’s ruling monarchy is the House of Orange.

  • The ring with the “Pumpkin Diamond” worn by Actress Halle Berry on her pinky finger for the 2002 Academy Awards.

Picture Courtesy: Onewed.com

Bottom line, a fancy orange is truly remarkable. If you find one don't let it go!

 

References 
Alyssa Morgan, Anthony Kampf and Eloïse Gaillou, Hidden treasures in Los Angeles at the Natural History Museum, InColor Spring 2013.
Cunningham, D.D. The Diamond Compendium, NAG Press,  2011, London. 
King J.M. GIA Colored Diamonds Color Reference Charts.Gemological Institute of America, 2006,  Carlsbad, California.
King J.M., Moses T.M., Shigley J.E., Liu Y.  Color grading of colored diamonds in the GIA Gem Trade Laboratory. Gems &Gemology, Vol. 30, No. 4, 1994, pp. 220–242, 
King, J.M., Gems & Gemology, Vol. 38, No. 2, 2002, pp. 162–163
Munsell.com
Wuyi Wang and Ren Lu, Orange diamonds with unusual color origin, Gems & Gemology, Spring 2013, Vol. 49, No. 1
Wuyi Wang, Matthew Hall, and Thomas M. Moses,Intensely colored Type IIadiamonds, with substantial nitrogen related defects, Gems & Gemology,  Vol. 39, No. 1, 2003, pp. 39–41

by YDCDL 

 

Tags: Orange, Nitrogen, Munsell, Color Decoding, Fancy Natural Orange

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