Topaz Treatment Guide

We hope this short guide will help to clarify the differences between the two most common ways to enhance natural white topaz; Coating and Irradiation.

Coating: They are two types of coating treatments; PVD and Diffusion.

PVD:  Physical Vapor Deposition: A thin optical film of a few micron is applied onto the surface of the genuine topaz through a process called vapor deposition. The type of enhancement and desired color will determine where the Topaz is enhanced on the table or the pavillion. The PVD process is unique, utilizing various minerals, oxygen and high vacuum. The process does not use harsh chemicals that would harm the environment and is considered a " green" process of choice compared to others. The treatment is fast and durable. The prime example of PVD enhanced topaz is the popular Mystic Topaz. Mystic Topaz have been sold successfully the last 10 years and have proven to withstand normal wear and tear. Special care has to be considered during the manufacturing process. Because the treatment is metal based, acids and gold plating solutions have been known to remove partially or totally the color. Ultrasonic cleaners may contain a pickling solution that would damage the enhanced surface of the gemstone. High heat from the jeweler's torch may adversely affect the refractive index, eliminating color intensity and brilliance. As a general rule all work to the jewelry should be done before placing the enhanced gemstone into the setting. Gems can not be recut or they will lose some or all their color.

Diffusion: First pioneered on white sapphire 20 years ago to change the color from colorless to blue, the same technology is available today for topaz.  Chemical agents in powder form are wrapped around each stones or group of stones forming a " cake" and heated at very a high temperature in a furnace. The topaz and the chemical agents bond together at the molecular level producing a permanent coloration on the entire surface (table and pavillion) of the gems. Many shades of blue, green, teal , light brown, pink, red and bicolor combinations are available. Glacier Blue, Teal, and Evergreen are three of the most popular colors. The treatment is fast, safe and durable, resistant to plating and pickling solutions, ultrasonic cleaners and is able to withstand the jeweler's torch for a short amount of time. Diffusion treatment has become well known and accepted in the U.S and especially in Europe were currents laws aim at reducing and gradually ban the irradiated gems. Gems can not be recut or they will to loose some or all of their color.

Irradiation:

The process of irradiation involves the exposure of the genuine white topaz to one or a variety of radiations. Exposure to Gamma rays and a final heat treatment to burn off undesired brown and green overtones that appear during the process is most commonly used to produce the Sky Blue color (light pure blue color.)  Sky Blue Topaz treatment with Gamma rays or Electrons does not have a high radiation  level and can be released immediately.   Exposure to neutrons in a linear reactor and or electrons in an electron accelerator combined with heat will produce the darker shades we know as London Blue and Swiss Blue. London Blue has a single radiation treatment while Swiss Blue has two. The treatment itself is quick (a matter of a few hours) but produces a significant amount of radioactivity.  Strict FTC regulations prohibit the release of the gems until they are tested at a safe level.  This "cool off" time can take from 6 months up to several years. The country of origin of the white topaz and the dosage (number of hours) of the treatment will have a direct effect on the intensity and shade of the final color as well as the cooling time.  All three colors, Sky, London and Swiss are heat sensitive and the jeweler's torch should be applied with caution as high heat may cause loss of color if applied for too long. Gems can be recut with little loss of color if any. If set in jewelry, the ultrasonic cleaner is safe for all three colors. The best way to clean your loose treated topaz is with a clean cloth and a few drops of window cleaner.

Please visit our store to see various coated and irradiated Topaz