Fancy colors are quite different in value determination. The most important indicator of value and salability is appearance. Regardless of what a lab report prints, the buyer will be the final judge of the overall impression that a stone makes.… Continue reading
Fancy color diamonds can be extremely valuable but can also be very inexpensive. Brown and yellow are the two most common colors occurring in diamond and therefore are the least expensive. Gray, which is less common, can also be considered… Continue reading
Brown tones are very common and are the least expensive of all the colors. Even the presence of a tint of brown discounts a diamond’s value substantially. Terms such as coffee brown or cognac are commonly used to describe the… Continue reading
This cognac brown, sometimes called orange, is worth more than most other browns but not nearly as much as its intense to vivid fancy yellow counterparts or colorless to near colorless counterparts.Diamonds do occur in every color of the spectrum… Continue reading
The term “fancy color” should be reserved for naturally occurring colors. The term should not be used when artificially treated color is involved.
Irradiated diamonds are stones that have been artificially treated to enhance or change a color. These treatments are commonly used on diamonds that have an undesirable tint to improve their value and salability. Continue reading
The cyclotron was the first of the irradiation methods to emerge in the early 1940s. In a cyclotron, ionized particles are accelerated to a high energy level by means of a high alternating voltage while circulating around in a strong… Continue reading
The nuclear reactor method obtains a more consistent color throughout the diamond. The major advantage of this method is its capacity. Instead of irradiating a few stones at a time, it accepts several hundred carats of rough or polished stones… Continue reading
Depending on the original stone color, the Van de Graff generator method is capable of producing bluish hues. The common cape (yellow) diamonds used in this process, change to a bluish-green or greenish-blue. These treated diamonds are very common, so… Continue reading
All three of these irradiation methods do not leave any detectable radioactive residue in the stone after treatment. This was not always true. Shortly after Marie Curie discovered Radium and Polonium in 1898, Sir William Crookes exposed colorless diamond crystals… Continue reading
In recent years, green diamonds have turned up that have been exposed to americium-241 (an artificial radioactive element) for color treatment. These are detectable using a Geiger counter.
Irradiated diamonds are valued by their appeal after the treatment is completed. As a buyer, be aware that they are worth far less than their natural counterparts. Even a very beautiful irradiated diamond should be valued on the basis of… Continue reading