Etienne Perret will
be speaking on this subject at the GIA's 4th International Gemological Symposium
August 27-29, 2006, in San Diego. For more information, visit www.symposium.gia.edu
.
Ever since diamonds were first discovered, connoisseurs have treasured the
occasional diamond that comes from the ground exhibiting a unique body color.
Being extremely rare, they ended up in the possession of royalty and the wealthiest
of collectors. Artists, experimenters and scientists have understood the potential
of making colored diamonds available to a greater audience and have tried
for generations to achieve colors similar to those seen in natural color diamonds.
The first color enhancing techniques were not permanent and often not disclosed.
Many of the early experiments with altering the color of diamonds by exposing
them to irradiation made the finished gemstone unsafe to wear. Sir William
Crookes, a physisist with a love of gemstones, in 1904 conducted a series
of experiments using radium salts to expose diamonds to radiation. The diamonds
turned a dark green. Unfortunately the treatment left the diamonds strongly
radioactive, to the point of being unwearable. Mr. Crookes donated a diamond
octahedron so treated to the British Museum in 1914, where it remains today:
still radioactive and still green.
Creative experimentation led to the development of treatment techniques yielding
safe, permanent, attractive colors in diamonds. Electron bombardment and electron
bombardment in combination with heat are two of the most common and safest
ways to alter a diamond’s color. Through the use of different combinations,
such as bombardment intensity and exposure durations, color treatment specialists
have been able to achieve a wide variety of colors.
Most colored diamonds available in the market are in a similar price range
to fine white diamonds. The diamonds chosen for treatment are usually somewhat
off-white in color exhibiting a slight brown or gray color (in the J to P
range, due to their lower initial cost). Parcels of diamonds often hundreds
of carats at a time are then sent to one of several treatment facilities located
within the United States or overseas. The cost to color treat diamonds usually
runs between $50 and $200 per carat for most of the standard colors, blue,
green, orange, yellow and black. Reds, purples and pinks are made from type
IIa diamonds that constitute less than 2% of all diamonds and therefore they
are much harder to achieve. They are also more costly due to their rarity.
Several diamond dealers in the United States and abroad stock a wide selection
of color treated diamond melee as well as a more limited number of colored
larger diamonds.
The rainbow of colors that are available today allows jewelry designers to
use far more than colorless diamonds in pieces of jewelry. They can now “paint”
with combinations of colors to create unique items that have never been possible
before with standard diamond jewelry. We now see rose gold pendants set with
purple and orange diamonds, yellow gold rings set with yellow, green and blue
diamonds or brooches using black and white diamonds.
Thanks to these new color treatment processes diamond jewelry in a wide variety
of colors is possible at a price, which is affordable to much of the jewelry
buying public.
