Coloring Diamonds:

Irradiating

Irradiation, the most controversial treatment (due in part to the fear that the stones might be radioactive)  has been used since the early 1940s to alter the color of diamonds.

You can take an "off-color" diamond, subject it to alpha or gamma particle radiation in a nuclear reactor or bombard it with electrons (the most popular method) using Van de Graaf generators and cyclotron linear accelerators or irradiate it with neutrons in a nuclear reactor to  create a wide range of lively blue, brown, attractive green, orange, and yellow colors.

It took until 1956 to develop a test to distinguish between natural and color-treated diamonds. Irradiation is still difficult -- sometimes impossible -- to detect by conventional Gemological examination.

Initially, some dealers used irradiation solely as a technique to salvage junk diamonds. For a while, this masquerading worked, at least till the market was flooded with junk diamonds.

Dealers have been selling color-treated stones at prices a fraction of those of their much rarer natural fancy-color diamond counterparts. Indeed, fine color- treated diamonds cost much less than fine white diamonds.

Some dealers who send diamonds to be irradiated do try to pass the end product off as natural. My advice: don't ever buy a so-called natural colored diamond without identification papers from the GIA.

A `treated diamond' dealer in New York City tells of a 3.00 carat flawless treated-blue diamond which he sold for around $10,000 total price. He estimates a natural blue with similar intensity and depth of color would have fetched in excess of $500,000.

A 1994 report by Israeli magazine Mazal U'Bracha said that a brand-new Russian treatment exists that can change a diamond's color.   

Known diamond irradiation dates back to 1904 when Sir W. Crookes, a British scientist, first buried stones in radium salts (This method is now illegal.) His experiments yielded beautiful green diamonds, but alas, they were radioactive.

For at least 30 years, radium-treated, radioactive green diamonds were sold to unsuspecting jewelry buyers.

How would you like to wear a radioactive diamond in your ear?

Don't think it can't happen!

Actual news headline!

"Radioactive Diamonds discovered in Europe"

Irradiated diamonds, some reportedly carrying dangerous amounts of radioactivity, were seized in early 1992 by the German government. Eight of the hottest stones registered 5,000 times above  guidelines set by the Nuclear Regulatory Commission. About 100 stones, most exceeding radiation standards "but not deemed" dangerous, were returned to dealers in Antwerp.

Of course, all diamond producers and dealers fiercely denyed that the diamonds came from their countries.