Gem Enhancement

“ Enhancement is defined as any process other than cutting and polishing that improves the appearance, durability, and/or availability of a gemstone.”

Gemstones don't usually reach the customer in their rough, natural state. Perhaps the most basic "enhancement", is the cutting and polishing of a gemstone in order to enhance its beauty. Other treatments may not be so obvious or quite so durable. Depending upon the material, some gems might be subjected to heating, irradiation, diffusion, filling fractures with certain compounds, bleaching, or dyeing.Gemstones are enhanced for a number of reasons:

Beauty: The treatment of a stone may alter and significantly improve the beauty of it. The modification may produce a stone that is cleaner and has better color.

Price: Fine natural gem rough is always in short supply and usually very expensive. If lower quality, cheaper, and more available materials can be treated or enhanced, the resulting production could look good and be available at a much lower price.

Demand: The demand for beautiful gem materials always exceeds the limited supply. The availability and affordability of enhanced stones fills the need and makes gemstones accessible in larger quantities.

Here are some of the most common treatments to enhance gemstones:

Heating — is a widely accepted enhancement process used on rubies, sapphires, amber, aquamarine, amethyst, citrine, tanzanite, zircon, topaz, and tourmaline. This treatment improves the transparency and/or color of the stones. Techniques range from simply throwing gems in a fire to be cooked or burned to employing sophisticated electric or gas furnaces at specific pressures and atmospheric conditions. Much corundum has been heated to enhance the color. Tourmalines are frequently heated to lighten the color. Blue zircons are usually heated and the resulting color is permanent. Since heating is generally permanent, heated stones do not require special care.

Irradiation — gems may change color if exposed to radiation. This may come from radioactive elements within the Earth's crust, or from artificial sources. Natural radiation may take millions of years to have an effect, while artificial irradiation may take only few hours to change a gems’s color. In some cases a gem will revert to it's original color, or may fade with time. Irradiation is often used with blue topaz. The stone is irradiated brown and then heated to produce the blue color. Irradiated stones do not require special care.

Oiling — is an ancient process used to enhance the clarity of emeralds. Oil is applied to the emerald and seeps into the fissures, which reach the stone's surface. Aside from improving clarity, this process may prevent brittleness. Oiling is generally not permanent and may need to be reapplied every few years. Special care is required for cleaning; repairing or mounting oiled stones. This treatment may not be permanent but it because of it's practicality it is generally accepted.

Diffusion — is another method occasionally used particularly on blue sapphires. During treatment, a colorless sapphire is coated with a titanium and oxide compound and exposed to heat. This enhances and/or changes the color of the stone and is quite stable. This kind of treatment is generally not accepted in the trade.

Most treatments that are done to improve the appearance of gemstones do not change the chemical composition of the stone. Some enhancements are difficult or impractical to prove definitively.

Beauty enhancing treatments can produce remarkable results. Less expensive materials can be transformed into more beautiful gemstones. However, because fine looking enhanced stones are generally much more common than similar quality untreated stones, their value may be less. Customers can decide what they want but they should not be mislead and should be informed of the existence of any treatments or enhancements before making a purchase. This information allows them to make their own careful and informed choices.

EMERALD: Usually oiled with colorless oil to improve appearance.
RUBY: Usually heated to improve color and appearance.
SAPPHIRE: Usually heated to produce intensity or light color and/or improve color uniformity.
TANZANITE: Usually heated to produce violet blue color.
AQUAMARINE: Usually heated to improve color.
BLUE TOPAZ: Usually irradiated and heated to produce blue color.
TOURMALINE: Commonly irradiated to intensify pink, red and purple color.
PEARLS: Commonly bleached to improve color and appearance.