Origin of name
The diamond has a unique and rare deep bluish-green
color, and the name of the diamond seems to have been inspired by this
color, reminiscent of the the color of the deep blue ocean.
Characteristics of the
diamond
According to the G. I. A. certificate the Ocean Dream
diamond is a fancy deep blue-green, triangular brilliant or trillion-cut
diamond, having a weight of 5.51 carats. It is the largest naturally colored
fancy deep blue-green diamond in the world.
History
The diamond seems to have originated in the Central
African Republic and the rough stone is known to have weighed 11.27 carats.
The diamond is presently owned by the Cora Diamond Corporation of New York.
Besides the above facts, other relevant information such as the mine of
origin, the date of discovery, the circumstances relating to the discovery,
The original owner of the diamond, the person or company involved in the
cutting etc. are conspicuously lacking. Even details of how the Cora Diamond
Corporation came to own the diamond are not not available.
The only details available about the diamond are the
features of the finished diamond as certified by the Gemological Institute
of America. The deep bluish green color is an extremely rare color among
diamonds and perhaps this may be the only naturally colored diamond on
record having this unique color. Thus in spite of it's relatively small size
of 5.51 carats, compared to other famous diamonds, the Ocean Dream earns the
distinction of being one of the rarest diamonds in the world. Artificial
color enhancement by irradiation may sometimes impart this unique color to
diamonds, that even a qualified Gemologist with a well trained eye may
sometimes presume the Ocean Dream to be artificially colored, at first
sight.
In our long list of famous diamonds the only other famous
green diamond we have come across is the 40.70-carat Dresden Green diamond,
which is a historical diamond of Indian origin. This gives an indication of
the extreme rarity of green color in diamonds. the De Beers collection of
fancy colored natural diamonds contain some rare specimens of natural green
diamonds.
The Ocean Dream diamond was displayed as part of the
Smithsonian's "The Splendor of Diamonds" exhibition, held between June 27th
and September 30th, 2003, alongside the De Beers Millennium Star, the Heart
of Eternity, the Moussaieff Red, the Alnatt diamond, the Pumpkin diamond,
and the Steinmetz Pink.
Present owners of the
diamond
The present owners of the diamond are the Cora Diamond
Corporation of New York.
The Chemistry of Green
diamonds
The Ocean Dream diamond was subjected to detailed and
exhaustive evaluation by the Gemological Institute of America, and it's
final conclusion was that the extraordinary deep bluish-green color of the
diamond resulted from it's exposure to natural radiation over millions of
years in the earth's crust.
Green diamonds do not fit into any one of the two
accepted classes of diamonds, type I and type II diamonds.
Type I diamonds contain minute quantities of nitrogen
impurities - less than 0.1 % - and account for 98 % of all naturally
occurring diamonds. Nitrogen imparts a yellow color to diamonds, whose
intensity depends on the concentration and distribution of Nitrogen atoms in
the crystal structure.
Type II diamonds are nitrogen-free or contain
undetectable quantities of nitrogen. They are sub-divided into two :- type
IIa and type IIb
Type IIa - They are nitrogen-free and structurally
perfect, and the resulting diamonds are absolutely colorless - D-color or
top-color diamonds. They account for 1-2 % of all naturally occurring
diamonds. OR
They are nitrogen-free and structurally imperfect,
resulting in a range of fancy colors such as pink, red, purple, brown etc.
They account for about 0.1 % of all naturally occurring diamonds.
Type IIb - They are nitrogen-free but instead contain
trace quantities of Boron as impurities. It must be noted that both
nitrogen and boron have atomic sizes comparable to that of carbon, and
therefore could be easily accommodated in the crystal structure. Boron
imparts a blue color to the diamonds and makes them semi-conducting. They
account for 0.1 % of all naturally occurring diamonds.
Green diamonds are also nitrogen-free, but their color is
not caused by another impurity or plastic deformation of the crystal
structure. Instead long exposure of the diamonds to natural irradiation
caused them to absorb magenta wave lengths which imparts the green color.
The intensity, and distribution of green color depends on the type of
radiation to which the diamond was exposed. If the diamonds were exposed to alpha
radiation emanating from radioactive sources such as naturally radioactive
uranium compounds, the green color may be just skin-deep as alpha radiation
does not penetrate deep enough. However if the diamond crystals were
bombarded by beta or gamma radiation that penetrates deeper into the
crystal, the diamond gets colored to a greater depth and occasionally the
entire interior of the stone turns green.
