FANCY COLOR DIAMOND

Fancy light yellow radiant cut diamond set in a pavé diamond setting.
Fancy yellow radiant cut diamond ring with a colorless diamond halo
Species:  Diamond
Mohs Hardness:  10 out of 10
Color:  Fancy color diamonds occur in nearly all colors.  More common fancy colors are browns, yellows and grays.  More rare colors are green, blue, pink, orange and red.
RI:  2.42
Birefringence:  None
SR/DR/AGG:  SR
Spectrum:  Varies with each color
  • Yellow, Brown & Orange:  Line at 415.5nm with weaker bands at 423, 435, 451, 478, 496 & 503nm.  The deeper the color, the more distinct the bands.
  • Red, Pink & Purple:  Broad band at 563nm and no sharp lines in the red.  Line at 415.5nm may be present.
  • Blue & Violet:  Type IA and IIA stones sometimes show weak to strong bands at 415.5nm, 478, 496 & 504nm, with a line at 595nm due to natural radiation.  Type IIB stones has no sharp bands with absorption increasing towards the end of the spectrum.
  • Green:  Usually some combination of lines at 415.5 nm, 496, 503 and 535nm.
Fluorescence:  Varies with each color
  • Yellow, Brown & Orange:  Can be inert, have faint, medium to strong reactions to LW, usually blue.  Inert to faint blue under SW.
  • Red, Pink & Purple:  Can be inert, have faint, medium to strong reactions to LW, usually blue.  Some Type II stones might fluoresce medium to strong orange under both LW and SW.
  • Blue & Violet:  Usually inert to LW.  Sometimes weak to strong blue, greenish blue, green, yellow or orange.  Rarely weak red to orange red, occasionally blue to greenish blue under SW.  Phosphorescence is blue to green, occasionally red to orangy red.
  • Green:  Some treated stones fluoresce very weak to strong yellowish green under LW and very weak to weak green under SW. 
SG:  3.52 (+/-0.10) 
Routine Treatments:  None
Additional Enhancements:  Irradiation, HPHT (high pressure, high temperature), coating

Fancy Color Diamond Facts

Magnificent Art Déco Era vintage platinum ring with a 2.25 ct old European cut fancy intense brownish yellow center, GIA certified
Magnificent Art Déco Era fancy colored diamond & near colorless diamond platinum ring

​Diamonds in the D to Z color scale become less valuable as more color is noticeable in their body color.  Fancy color diamonds are the opposite, increasing in value as the intensity of color increases.

The color of diamonds are caused by various reasons.  Brown, pink, purple and red diamonds are caused by an imperfection in the diamond's crystal lattice.  Gray and blue diamonds are due to the presence of boron during formation.  Yellow & orange diamonds are caused by the presence of nitrogen during formation. Green diamonds are caused by radiation.  Black diamonds are caused by dark graphite and iron inclusions.

Diamonds can occur in nearly all colors including yellow, brown, gray, black, blue, pink, orange, green, and red.  These colored diamonds are graded using GIA's fancy color grading system.  The image below illustrates the intensity of color saturation. ​

Fancy Color Diamond Gallery

Color Enhanced Diamonds

irradiation

Treated diamonds, before (top) and after (bottom).
Photo courtesy of US Diamond Technologies

​Diamonds can be exposed to a strong radioactive treatment that alters their natural color, often turning an unattractive gray diamond into a very vivid, fancy colored diamond.

surface coating

An imperfect diamond in the d to z color range has been coated with a pink surface coating, giving the appearance of a fancy pink diamond
A coating gives this natural diamond a pink appearance

A somewhat durable surface coating can be applied to a diamond, giving the appearance that it is a fancy color.
Photos courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA)