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Early in the 20th century, attempts to give diamonds some color
were pretty coarse, basically involving using vegetable dyes and ink
to coat the stones. But these coatings were not permanent and once
detected, could be easily removed by cleaning the diamonds with acid.
The breakthrough in color enhancement came in 1905 when an English
chemist Sir William Crookes permanently changed the color of diamonds
by exposing them to radiation. He did this by burying some diamonds
in radium – bromide salts for an extended period of time.
This permanently changed the color of those diamonds on the surface
to different hues of blue and green. However, there was a problem
– the stones were dangerously radioactive after the process,
and obviously, completely unusable. Nevertheless Sir William Crookes
proved that diamonds could be irradiated to change their color,
and the search was on to find the safe means of doing so.
In 1942, JM Cork, a scientist at the University of Michigan, used
a device called a cyclotron to safely produce shades of green in
diamonds by bombarding them with high-speed alpha and proton particles.
Even though the process created some residual radiation in the stones,
it dissipated within a few hours. Others continued where Cork left
off, but the problem was that only a very limited range of different
hues of green could be produced with a cyclotron. The challenge
was to produce the entire range of colors consistently. In the early
1950’s some gemologists began to combine the process of irradiation
with annealing (heating) - and this led to the creation of a multitude
of new colors. |
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| New Levels of Safety |
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| When electron accelerators began to be utilized in diamond
irradiation during the 1970’s and 1980’s, color-enhancement
of diamonds reached new levels of safety. The process could
now be done without leaving even residual radiation in the stones.
At the moment, the electron accelerator method is favored by
most reputable colored diamond manufacturers, including Lotus.
With safe methods of diamond irradiation in place by early
1990’s (and with treatments of other gemstone more widely
accepted in the industry), the manufacture of colored diamonds
greatly picked up the pace, with many jewelers and designers
now regularly featuring and using these diamonds. The challenge
is now to create colors in diamonds efficiently and increase
the public awareness about these gems.
In the meantime, the search for answers goes on. We’re
yet to solve the mystery of how certain colors and shades
- like pink - really appear through enhancement, while the
discovery of new colors - like red - is still to be unveiled. |
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