Fancy chameleons are natural gems that belong to the family of colored diamonds and have a very particular characteristic: they can change color. These stones normally have an olive green hue which can temporarily transform into a light yellow when exposed to heat or when kept in the dark.

The color change in chameleon diamonds is not permanent, in some stones it usually lasts as long as it takes to go back to the initial conditions of light and temperature, but the color variation is astounding and obvious.

The first record of them was in 1943 when Peter Kaplan noticed that a gem, graded as yellowish-green, changed to a dark olive when it came into contact with a hot polishing disc. The story goes that the gem was later sold as its original color grade. The buyer the next morning, took it out of the jewelry box, noticed the color change and immediately took it back to Kaplan for a refund.

The causes of the color in these enigmatic diamonds is still unknown. Within its crystalline lattice, high concentrations of nitrogen, hydrogen, and nickel were found. It is presumed that the interaction between the first two elements is the cause of the chameleon effect of the stone.

It's sources are also a mystery. Although the majority of them were purchased in India, there are records of chameleons extracted in Brazil, Venezuela, Sierra Leone, Borneo, and Ivory Coast.

The rarity of chameleon diamonds make them the target of collectors and investors. The scientific community also shows a special interest in studying these stones as their properties and the causes of the color change phenomenon are still an enigma.

Fancy Chameleon Types

The fancy chameleons are classified into two categories according to the GIA:

• Classic: the color change goes from an olive green to a yellowish orange. They go from dark to light. Most chameleons are classic.
• Reverse: They are light yellowish diamonds that temporarily transform into olive green when the light conditions change. They go from light to dark.

Tones and Intensities

One of the most important features of chameleon diamonds is that they are not available in intense or vivid tones. They are graded in: Fancy, Fancy Dark and Fancy Deep.

Another property is that they possess diamond fluorescence, which is the glow that diamonds emanate when exposed to UV light.

The fancy chameleons are not usually found with pure hues, at least two combinations of Green, Yellow, Brown and Gray will always be seen.

The most common color combinations are:

Gray Yellowish, Grayish Yellowish, Gray Greenish, Green-Yellow, Brownish Greenish and Brownish Yellowish.

The most valued and desired colors are those with intensity and tone Fancy Dark and Fancy Deep since in these gems the color change is more noticeable.

How to recognize a Fancy Chameleon?

There are two ways to check if a diamond can change color: with heat and with darkness.

The transformation of these stones is due to two effects, thermochromism; which refers to a reaction to heat; and photochromism; which is a response to changes in the light conditions.

To verify the first, the gem should be exposed to a temperature higher than 150 degrees Celsius and observe if it shows any physical changes. On the other hand, photochromism can be verified by storing the diamond in a completely dark place for a period of no less than 24 hours to then expose it to natural light. If it’s a chameleon, the color change will be obvious.

Famous Chameleons

The biggest and most popular Fancy Chameleon is the Chopard Chameleon Diamond. It is 31.32 carats. This gem is practically inclusion’s free, something extraordinary for diamonds of this size. It was bought by Genevan Jeweller and is now the centerpiece of a ring surrounded by tiny yellow diamonds.