Experimentation in diamond synthesis may soon bring the
world more blue diamonds
Natural blue diamonds are among the rarest and most coveted,
thanks in part to the mystery and allure of standouts such as
the Hope or Eugenie Blue. Now comes word the dearth of blue diamonds
may ease somewhat with the production of a synthetic counterpart.
Even synthetic blue diamonds are rare and difficult to manufacture,
says Alex Grizenko of Ultimate Created Diamonds, Golden,
CO, which markets the material in the U.S. But production is
under way in Russia.
The technology dates back to the 1970s, when the Soviet Union
started to synthesize diamonds for industrial applications. Blue
diamonds were of particular interest because of their hardness,
high temperature resistance and electrical conductivity. (De
Beers in England, General Electric in the U.S. and Sumitomo in
Japan have also experimented with color diamond synthesis, but
not for commercial purposes.)
How and How Much
Most laboratory grown blue diamonds are Type IIb, though
a very rare Type IaA blue diamond from Australia also exists
(for a discussion of diamond types, see Professional Jeweler,
August 1999, p. 30). The color is inherent, not induced by a
separate step such as heating or irradiating.
Because the blue diamonds are harder than other colors to synthesize,
they usually are small (mostly under half a carat) and range
from $2,000 to $5,000 per carat wholesale.
The future promises increased production of the synthetic
blues to be used in jewelry. For this reason, gemologists and
sales associates should be prepared to tell the difference whenever
possible. The winter 1998 issue of Gems & Gemology, the quarterly
journal of the Gemological Institute of America, contains a chart
showing differences between natural color blue diamonds
and synthetic counterparts. Here are some of the characteristics:
- Magnification. In synthetic blue diamonds, metallic
opaque inclusions are often visible under low magnification or
even to the naked eye. These particles from molten metal
alloys in the presses in which they're grown become trapped
in the crystal during growth. Opaque metallic inclusions aren't
seen in natural blue diamonds.
- Magnetism. These metallic alloys can be magnetic if
present in a faceted diamond in sufficient size.
- Fluorescence/phosphorescence. With synthetic blue
diamonds, the typical fluorescence in short wave ultraviolet
radiation is a weak to moderate blue or greenish blue. While
this feature may be observed in natural color blue diamonds
also, the synthetic counterpart is more likely to phosphoresce
(the color glows for some time after the short wave ultraviolet
unit is turned off.) Fluorescence also can reveal angular growth
patterns and graining, which is typical of synthetic diamonds.
- Color zoning. Short wave radiation in synthetic
blue diamonds may reveal angular graining such as cross or hour glass
If you examine a blue diamond and can't find any diagnostic characteristics
that would indicate a synthetic, don't assume it's natural yet.
In cases where determinations are elusive by conventional tests,
send the stone to a qualified gemological laboratory.
by Robert Weldon, G.G.
||Opposite: These synthetic blue diamonds from
Russia range from 0.18 to 0.33 carat. Diamonds are courtesy of
Ultimate Created Diamonds, Golden, CO.
|Right: Synthetic blue diamond has eye
visible metallic opaque inclusions seen only in laboratory grown
stones. Diamonds are courtesy of Ultimate Created Diamonds,
||Left: Closeup of the same diamond shows the angular,
rounded shape and opaque quality of the metallic inclusions,
which underscore its lab grown origin. Diamonds are courtesy
of Ultimate Created Diamonds, Golden, CO.
Copyright © 1999 by Bond Communications.