The Truth About Gemstones

Gemstone treatments, fakes & composites

Most gemstones used in jewelry have been treated to improve their appearance. Treated gemstones can be a good choice when you know what you are buying and pay a price that reflects a stone's true quality.

Common Gemstone Treatments

Heat and radiation can change or enhance colors.

Diffusion is used to deepen color. It only changes a stone's outer layers.

Oil and waxes are used to enhance color by filling-in fine surface cracks.

Fracture filling, which coats stones with a clear or colored epoxy resin or other substance. This treatment fills-in cracks, which improves the appearance of the stone.

Laser drilling removes inclusions (flaws), improving clarity.

Some gemstone treatments are permanent, others are not. Heat treatments create permanent color changes in some stones, but temporary changes in others.
Always ask if the jewelry you intend to purchase contains treated gemstones. If it does, ask which treatments were used and if those treatments are permanent.

Imitation Gemstones

Imitation, or simulated, stones may look like the real thing, but that's where the similarities end. They do not have any of the same physical characteristics of a natural or synthetic gemstone.

Imitation stones are often made of glass or plastic and most can be detected easily by a jeweler.

A stone that's mounted on a solid back might have foil underneath to make it look more brilliant or change its color.

Moissanite is a newer diamond substitute that's even fooling the pros. It is not a fake—it is a synthetic version gemstone that's only been found in very small quantities in nature.

It's a problem when moissanite or other substance that resembles a similar gem is resold as the more expensive gemstone by someone who either doesn't know the difference, or intends to deceive.

Watch for Composite Stones

A composite is a smaller piece of a desirable, genuine stone that's been combined with a larger chunk of an inexpensive or imitation gemstone.


Doublets are composite stones where a larger, inexpensive chunk is topped by a thin slice of a genuine stone. The division usually isn't obvious without magnification.

One type of doublet sandwiches a colored bonding agent between two clear, inexpensive stones to mimic a colored gemstone.

Triplets are composites assembled in three parts.

Be a Careful Shopper

Jewelry made with synthetic, treated, and imitation stones can be gorgeous—there's no reason to avoid it. What you do want to avoid is paying too much for misrepresented merchandise.

Read as many resources as possible and start looking more closely at jewelry. Ask questions when you shop. It won't make you an overnight pro, but in time it will help you become a more savvy consumer.