Frequently Asked Questions

What are lattice diffusion sapphires?
Lattice diffusion is a treatment process that uses heat and chemicals to diffuse an element into a gemstone to artificially change its color. Lattice diffusion treated sapphires can be any color. In some cases the added color is shallow. In others, it goes all the way through the stone.

How do I know that a sapphire is a real padparadscha?
The definition of Padparadscha has always been debated. Gem Lab has studied the history of the term and its modern use and indicates on sapphire identification reports when a sapphire, in our opinion, meets the criteria for being described as Padparadscha.

How does lattice diffusion affect a sapphire’s value?
Sapphires treated by lattice diffusion generally cost less than sapphires that have been treated by heat without the addition of color-causing chemicals or sapphires that have not been treated.

What if I suspect gem material I’m submitting has been treated or is a product of gem synthesis?
You are required to disclose if you know, suspect, or are unsure that the material has undergone treatment or is a product of gem synthesis. About disclosing treated or synthetic gem material when submitting stones to GIA for service.

What treatments does TGL test for?
Colored gemstones are tested/examined for heating, fracture filling/clarity enhancement, coating, dyeing, and diffusion.

Pearls and diamonds grading

Is citrine treated?
Because yellow quartz colors are rare in nature, most citrine is the result of heating, which converts less-valuable shades of purple amethyst to the golden shades of citrine.

What is a “created” emerald?
Synthetic emeralds are generally marketed with the name of the company and the word “created” rather than synthetic. “Laboratory-grown,” “laboratory-created,” “[manufacturer name]-created” or “synthetic” are all permitted to describe man-made materials in the FTC Guides.

How do I know if a blue spinel has cobalt in it?
Although cobalt blue spinels do owe their vivid color to traces of cobalt, it’s the color that makes them valuable, not the presence of that coloring agent. If your spinel has a rich saturated blue color, it is rare and valuable whether or not it contains traces of cobalt.

Is blue topaz radioactive?

National regulations around the world control the release of gems from irradiation facilities to ensure that it meets safety standards. In the United States, the standard for release and import of topaz is a small fraction of the background radiation that everyone is exposed to every day.

What is the difference between treatment and enhancement and what are they?
There is no difference between the terms “treatment” and “enhancement”. They are both used to describe any artificial process that alters the appearance, especially the color or clarity, of any gem material.

How does heat treatment affect a sapphire’s value?
Heating is an accepted treatment for sapphire. But for fine quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire’s rarity and value.