Origin of name
The Williamson diamond gets its name from Dr. John
Williamson, the renowned Canadian Geologist, who discovered the diamond in
1947 in his own mine in Tanzania (Tanganyika), which is known as the
Williamson diamond mine or Mwadui diamond mine, and subsequently presented
it in the rough state, as a wedding gift to Princess Elizabeth (later Queen
Elizabeth II) in the same year.
Characteristics of the
diamond
The Williamson diamond is a pale pink, flawless
(exact color and clarity grades not known), round brilliant-cut diamond,
weighing 23.56 carats. In the list of famous pink diamonds below Williamson's
diamond occupies the 9th position.
List of famous pink
diamonds
|
S/No |
Name |
Carat Weight |
Color |
|
1 |
Darya-i-Nur |
186 |
light pink |
|
2 |
Nur-ul-Ain |
60 |
light pink |
|
3 |
Steinmetz pink |
59.60 |
fancy vivid pink |
|
4 |
Shah Jahaan |
56.71 |
light pink |
|
5 |
Agra |
32.34 |
fancy light pink |
|
6 |
Pink Sunrise |
29.79 |
fancy pink |
|
7 |
Rose of Dubai |
25.02 |
fancy pink |
|
8 |
Mouawad Lilac |
24.44 |
fancy purplish pink |
|
9 |
Williamson |
23.56 |
fancy pink |
|
10 |
Graff Pink Orchid |
22.84 |
fancy purplish pink |
|
11 |
Mouawad Pink |
21.06 |
fancy pink |
|
12 |
Hortensia |
20.00 |
light orange pink |
|
13 |
Graff Pink Supreme |
10.83 |
fancy pink |
|
14 |
Conde Pink |
9.01 |
light pink |
Williamson diamond is a Type IIa diamond, free of
nitrogen and other impurities. They are said to be chemically pure diamonds.
Normally these diamonds have structurally perfect crystals and are
absolutely colorless. They constitute about 1-2 % of all naturally occurring
diamonds. However a small percentage of these diamonds have undergone
plastic deformation in the crystal structure, by the twisting and bending of
crystal units, which change the absorption spectrum of the diamond causing
rare fancy colors such as pink, red, purple and sometimes brown.
The occurrence of pink diamonds is much less than 0.1 %
of all naturally occurring diamonds. In the Argyle mines of Western
Australia, the main source of pink diamonds in the world today, a
statistical analysis has shown that only a single carat of pink diamond is
produced for every 1,000,000 carats of gem-quality rough diamonds. This
works out to an unbelievably low occurrence of 0.0001 %.
Another interesting feature of pink diamonds seen in the
above table, is that except for the first diamond, the Darya-i-Nur, all
other diamonds are less than 100 carats in weight. In fact most of the
diamonds are around 20 to 30 carats in weight. In the Argyle diamond mines,
the average size of pink diamonds produced is much less than this, and is
only about 1.0 carat in weight. Thus pink diamonds have a restricted size as
compared to white and yellow diamonds.
History
The Williamson diamond was the first notable diamond to
be produced in the Williamson diamond mine, in Tanzania, after its discovery
in 1940, by Dr. John Williamson, the Canadian Geologist. The rough diamond
weighed 54 carats, and was presented to Princess Elizabeth and Prince
Philip, upon their wedding in 1947. The diamond was cut and polished by
Briefel and Lemer of London in 1948. The Princess then commissioned the
jewelry firm of Cartier's to design a flower-shaped brooch for her with the
23.56-carat Williamson diamond as the centerpiece. The brooch was designed
by Frederick Mew of Cartier's in 1952.
Williamson Diamond Mine -
Tanzania.
Diamond mining in Tanzania started in the 1930s, with
several small scale mines beginning operations, but production was
insignificant. Then in 1938, the operators of the Mabuki diamond mine
invited Dr. John Williamson, a Canadian Geologist to conduct a geological
survey of the area, with a view of identifying prospective diamond mining
areas. In 1940, Dr Williamson, positively identified a gem-bearing
Kimberlite pipe, about 160 Km south of the town of Mwanza, on the shores of
Lake Victoria, in the Shinyanga region of Tanzania. Dr. Williamson named the
mine, Mwadui mine, after a local chief of the area, but subsequently the
mine became popularly known the Williamson mine. The diamond-bearing
volcanic pipe had a surface mining area of 1.46 Sq. Km. and it was one of
the largest economically exploitable diamond-bearing volcanic pipe in the
world.
Dr Williamson began the exploitation of the mine as an
open pit mine, but soon encountered difficulties in procuring the
necessary funds and equipment, due to the outbreak of the second world war.
But, immediately after the war, he was able to invest sufficient funds for
the development of the mine, and by 1950 the Williamson diamond mine became
the first significant diamond mine in Tanzania, and outside South Africa.
Dr. Williamson installed state-of-the-art equipment in his mine and was
responsible for introducing several technical innovations in diamond mining.
Production output in the mines were quite attractive in
the 1950s and 1960s, when the average output was between 500,000 and 750,000
carats per year. with a peak production of 925,000 carats in 1966. But,
today production levels have dropped to an average of 300,000 carats per
year. The mine that is still under production, has produced a total of
around 20 million carats of diamonds since it's inception. Presently the
mine employs about 1,100 workers, and the depth of the mine is about
90m (300 ft).
Dr John Williamson died in 1958, at the age of 50 years,
and immediately after his death, his heirs sold the mine to a joint company
of De Beers South Africa and the Colonial Government of Tanganyika, for a
sum of £ 4 million sterling. Tanganyika became independent on Dec 9, 1961,
with Julius Nyerere as Prime Minister. In 1964, Tanganyika formed a union
with neighboring island State of Zanzibar, and emerged as a sovereign
republic known as the United Republic of Tanzania, with Julius Nyerere as
President and Sheik Abeid Amani Karume the president of Zanzibar, as the
Vice President. In 1971 almost 10 years after the independence of
Tanganyika, the Williamson diamond mines were nationalised. From 1971 to
1994 the mine was managed by the Government of Tanzania, but there was
serious deterioration in the mines performance attributed to inadequate
capital investment, a bloated labour force, loss of skilled, foreign
management and engineering staff, and a decrease in the grade of the ore. In
1994 the Government of Tanzania, re-invited De Beers of South Africa to
invest in the mine, and De Beers bought over 75 % of the shares of the mine,
25 % being retained by the Government. De Beers has now taken over the
management of the mine, and has improved the efficiency of the mine, by
reducing the workforce, investing in modern equipment and technology, and
bringing in foreign expertise for operations of the mine and further
exploration. Studies have already been concluded by the company to look into
the possibilities of extending the operations of the mine, by going further
deep into the diamond-bearing Kimberlite pipe, extending the life of the
67-year old diamond mine.
