The Dresden Green
In the rough, greenish diamonds tend to occur as one of three
types: a stone, often a crystal shape, possessing a light tinge rather like the
color of water in a swimming pool; a stone with a dark green skin; a
yellowish-green stone characterized by a degree if lubricity. After being cut
and polished, diamonds of the first and second types usually lose their greenish
color to become white gems or, alternatively, light yellow stones known as
"silvery capes". The few truly green faceted diamonds therefore originate from
the third type. The famous collection of De Beers Fancy Colored Diamonds, which
has been displayed throughout the world includes some beautiful examples of
green diamonds.
Since this is the story of a truly rare gem, a scientific
explanation for the phenomenon of green diamonds is needed. The green color is
usually caused by the crystal's coming into contact with a radioactive source at
some point during its lifetime, and in geological terms, this is measured in
millions of years. The most common form of irradiation diamonds chance into is
through bombardment by alpha particles which are present in uranium compounds or
percolating groundwater. Long exposure to these particles forms a green spot on
the surface of the diamond, or sometimes produces a thin green coating which is
only skin deep and can easily be removed during the faceting process. But
bombardment by beta and gamma rays well as neutrons will color the stone to a
greater depth and in some cases turn the whole stone's interior green.
Heating the stone might sometimes improve the color but care
must be taken to keep the temperature below 600°C, because at this temperature
the green color is likely to turn to a light yellow or brown. The change in
color is caused by the change in the crystal's lattice structure. Before
bombardment by radioactive particles the crystal's lattice was stable but the
initial radioactive shock was sufficient to disturb the equilibrium and produce
a green coloration. Tempering will distort the lattice further and produce
another change of color. This phenomena is analogous to a piece of elastic that
has been overstretched; it will stretch back so far, but never returns to its
original length. Similarly, after a treatment the diamond's lattice remains
permanently distorted. 
The Dresden Green out of its setting.
Research has disclosed that green or irradiated diamonds are
more common from alluvial deposits, although they are found in primary sources,
usually in the upper part of the diamond-bearing volcanic pipe, but green
diamonds of any size are rare. The Dresden Green, which probably weighed over
100 (old) carats in its rough form, is unique among world famous diamonds. It
was originally probably an elongated unbroken stone since greenish diamonds
rarely occur as cleavages.
The Dresden Green gets its name from the capitol of Saxony
where it has been on display for more than 200 years. The earliest known
reference to its existence occurs in The Post Boy, a London new-sheet of the
1700's. The issue dated October 25th - 27th, 1722 included this article:
"On Tuesday last, in the afternoon, one Mr. Marcus Moses,
lately arrived from India, had the honor to wait on his Majesty [King George I
(ruled 1714-27)] with his large diamond, which is of a fine emerald green color,
and was with his Majesty near an hour. His Majesty was very much pleased with
the sight thereof. It is said there never was seen the like in Europe before,
being free from any defect in the world; and he has shown his Majesty several
other fine large diamonds, the like of which 'tis said were never brought from
India before. He was also, the 25th, to wait on their Royal Highnesses with his
large diamond; and they were surprised to see one of such largeness, and of such
a fine emerald color without the help of a foil under it. We hear the gentlemen
values it at £10,000."
Marcus Moses was an important diamond merchant in London
during the first part of the 18th century - he had once been involved with the
Regent Diamond.
Another early reference to the Dresden Green is found in a
letter dated from 1726, from Baron Gautier, the "assessor" at the Geheimes
Rath's Collegium in Dresden, to the Polish ambassador in London, which speaks of
the green diamond being being offered to Frederick Augustus I (1694-1753) by a
London merchant for £30,000. This ruler, known as Augustus the Strong, was
responsible for the construction of some great buildings in Dresden, which he
duly filled with great collections of rare and expensive treasures - sculptures,
paintings, and objects d'art. He accumulated a collection of crown jewels as the
ruler of Saxony, and when he was elected to the throne of Poland in 1697 he
commanded new regalia be made for his coronation. Frederick Augustus set aside a
group of rooms in Dresden Castle to house his collection of jewels and other
treasures, and named them the Green Vault, their interior decoration being
trusted to Persian designers. The final result was considered to be one of the
finest examples of Baroque. Nowadays, the contents of the Green Vault is housed
in a contemporary Albertinium Museum, built on the site of the original castle
that was destroyed during World War II.
A model of the green diamond was owned by the eminent
physicist Sir Hans Sloane (1660-1753), whose collection of books, manuscripts
and curiosities formed the basis of the British Museum. When Sloane retired from
active work in 1741 his library and cabinet of curiosities had grown to be of
unique value and on his death he bequeathed his collection to the nation, on the
condition that Parliament pay his executors £20,000. The bequest was accepted
and went to help form the British Museum, opened to the public in 1759.
Neither George I nor Frederick Augustus I purchased the green
diamond; instead it was the latter's son, Frederick Augustus II (1733-1763) who
became its first royal owner. He bought the Dresden Green from a Dutch merchant
named Delles, at the Leipzig Fair in 1741. Various figures are given for the
purchase price but the most interesting was found in a letter to Frederick the
Great, King of Prussia (1712-1786), which states that "For the siege of Brünn
the King of Poland was asked for heavy artillery. He refused due to the scarcity
of money; he had just spent 400,000 thaler for a large green diamond." On orders
of Frederick Augustus II, the court jeweler, Dinglinger, set the diamond in the
Decoration of the Golden Fleece, but this setting lasted for only four years and
was broken up in 1746. The king then commissioned the goldsmith Pallard in
Vienna, to design another Golden Fleece incorporating both the Dresden Green and
the Dresden White, a cushion-shaped diamond weighing 49.71 carats. 
The Golden Fleece ornament with the Dresden White (top). The center
third of the ornament which encompasses the Dresden Green was saved
from disassembly and remains part of the present ornament.
From 1756 to 1763 during the continued hostilities of the
Seven Years War, the contents of the Green Vault were removed for safety to the
fortress of Königstein, located in southeast Dresden by the Elba River. Several
years after the war, which saw the defeat of Saxony, Pallard's Golden Fleece
ornament was also broken up. In 1768 another jeweler, Diessbach, worked the
green diamond into a hat clasp along with two other white brilliants, weighing
almost 40 carats total, and a number of smaller diamonds. The Dresden Green
survives in Diessbach's ornament today.
In 1806 Saxony became a kingdom and the royal line continued
until 1918 when the last king abdicated. The contents of the Green Vault
remained on display to the public until the beginning of World War II. In 1942
they were removed again to Königstein, thus escaping the shattering air raid by
the Allied Forces on the night of February 13th, 1945 which divested Dresden.
Later that same year the Soviet Trophies Commission, which had made its
headquarters in Pillnitz Castle near the center of the ruined city, took the
contents of the Green Vault to Moscow, the Crown jewels being among the first
items to travel there. They were returned in 1958. 
The Dresden Green's facet layout, captured from its Gemcad file. This design
originally appeared in the winter, 1990 issue of Gems & Gemology, and was
converted into Gemcad by Robert Strickland in 1998. It is the most faithful
retro-engineered replica of the Dresden Green I have ever seen, and thus, can
be checked off of the list of famous diamonds to be converted into Gemcad.
The Gemological Institute of America examined the stone in
1988. The Dresden Green Diamond was proved to be not only of extraordinary
quality, but also a rare type IIa diamond. The clarity grade determined by GIA
was VS1 and the gem has the potential of being internally flawless. (This means
that the stone's flaws are near the outer surface, probably the pavilion of the
stone, where a slight re-cutting could remove them and improve the clarity of
the stone.) The gem measures 29.75 × 19.88 × 10.29mm. Unbelievably, the GIA
graded the symmetry good and the polish very good. This is amazing for a diamond
cut prior to 1741. Also, the Dresden Green has a natural green body color. This
is extremely rare. Diamonds with green skins or scattered green patches are more
common. 
Another photo of the Dresden Green, photographed
from the underside with the culet facing outward.
In the summer of 2000, Ronald Winston completed arrangements
for the Dresden Green to be exhibited in October, 2000, in the Harry Winston
Gallery at the Smithsonian Institution, alongside the world's most famous
diamond: the Hope. The 40.70-carat Dresden Green the largest and finest
natural green diamond ever found, has long been considered a "sister" to the
Hope Diamond, which it closely matches in size, intensity of color, and
historical importance. Friday, October 14th, marked the official public opening
of this remarkable exhibition.
It was the twelve-year quest of Ronald Winston to bring these
two diamonds together. "There is only one other diamond, the Dresden Green,
which comes close to the Hope Diamond in rarity and uniqueness," said Ronald
Winston. "I always hoped that in my lifetime I would be able to witness the Hope
Diamond and the Dresden Green on exhibit together. This would have been the
crown in my father's 'Court of Jewels,' an unparalleled collection which toured
the country in the 1950's and included some of the most famous diamonds in
history."
The Dresden Green remained at the Smithsonian until January
of 2001, when it returned the Albertinium Museum in Dresden, where it remains to
this day. Sources: The Harry Winston website, Famous Diamonds by Ian
Balfour, The Nature of Diamonds by George E. Harlow, the Gemstone
Forecaster, and various sites scattered around the internet.