Treatments and Synthetics

Treatments
Topaz seems to be becoming the gemstone with the widest variety of treatments imposed to affect its color.  The listed treatments here are considered acceptable by the industry.

Heat

Topaz has been heat treated to improve color for decades, maybe even centuries.  For example, almost all pink topaz is created by heat treating yellow topaz.

Irradiation

Several decades ago, a technique was introduced of irradiating topaz colorless topaz to produce attractive shades of blue.  Nearly all of the blue topaz on the market today has been irradiated in this way.  Sky Blue, London Blue and Swiss Blue are usually created using this treatment.  In Europe this treatment is controversial and on its way to being banned because of the possible residual radioactivity of the gemstones.

Diffusion

In recent decades, another method for improving the color of topaz was developed.  It involves coating the colorless topaz with a specific chemical and then heating it at very high temperatures.  Only the surface layer of the gemstone is affected while the center remains colorless (you would not be able to tell unless you cut it in half). This is a relatively durable treatment.

Coating

Some topaz gemstones are treated with an extremely thin film of mineral or metalic materials and then placed in a vacuum.  This process creates topaz that are a wide variety of irridescent, eye catching colors.  They are called “Mystic Topaz”, and new terms are coined every week.

Synthetics

Synthetic topaz is not very prevalent on the market because natural topaz is so available.  In fact, synthetic topaz can be found at the same price if not more expensive than natural topaz. Most jewelers will specify whether it is synthetic.

Imitation

Topaz is imitated by quartz (citrine) and glass.  It can be distinguished from these by a scratch test, since topaz is harder than both of these materials.  If you rub a peice of quartz against a topaz, the quartz will scratch but the topaz will not.

Natural: This is what natural, untreated white topaz looks like Irradiated: After white topaz is irradiated, it can acheive this color of electric “swiss blue.” Coated:  The eye catching “mystic topaz” is created using the coating treatment. Coated:  Many gemstone producers are experimenting with the coating treatment to create a wide range of “mystic” stones.  This one is called “twilight fire.” .