To summarize our previous blog update on Nano Gems: To keep Nano Gems true to color, it is very important to fire in silver clay with an azure, or a hole for light to pass through, behind the gem. Without an azure, Nano Gems can change color, get dull or lose luster. Nano Gems can also change properties when they are fired above certain temperatures, and the maximum temperate that a Nano Gem can be fired to varies from gem to gem. We have found that all of the Nano Gems we currently carry are safe to fire up to 1675°F / 913°C on an open shelf in silver clay, with the exception of the Dark Orange and Orange, which can be safely be fired up to 1650°F / 899°C on an open shelf in silver clay.
The first tests of our newest Nano Gems were in FS999, fired at its recommended firing schedule of 1650°F / 899°C, and EZ960 at EZ960’s recommended firing schedule of 1675°F / 899°C. Both samples where fired open shelf for two hours. In both samples, the top row of Nano Gems all have azures behind them. They stayed true to color and brilliance. The Nano Gems on the bottom rows we inserted into the clay without an azure. Most changed color, lost luster and became dull. When the gems were removed from the sample after firing, their properties remained altered.
The next tests were the Nano Gems with azures fired in Magic Carbon. The samples were FS999 fired at 1650°F / 899°C, and EZ960 fired at 1590°F / 865°C. Both samples were fired for two hours at their recommended firing temperatures when firing in carbon. As with the first batch of Nano Gems, all fired beautifully without any change. The only exception was the Emerald Green, which turned black. As of this writing, we have not tested silver clays and Nano Gems in coconut or coal carbon.
Other tests were the Nano Gems with azures in base metal clays fired in coconut carbon. One sample was FASTfire BRONZclay fired at 1525°F for one hour, and the other was Five Star Copper Clay fired at 1700°F for two hours. The Nano gems fired in the FASTfire BRONZclay all stayed true to color, but they all lost some luster and became dull. The exception was the Emerald Green which turned black. All of the Nano Gems in the Five Star Copper Clay all had substantial changes in color, luster and clarity. Nano Gems can take on different properties depending on the clay they are fired in. We highly recommend testing before firing the Nano Gems in base metal clays. (See picture below on the left).
A pendant was made to test all of the Nano Gems in FS999 to see if they can be flash fired with enamels. The bail on the sample needed to be repaired, and the sample was re-fired at the FS999 recommended firing schedule twice. Some of the lighter toned gemstones got a slight yellow halo around the gem. This yellow halo is more evident in the photograph than when looking at it with a naked eye. Multiple firings of the Nano Gems at a silver clay’s recommended firing schedules, can alter the properties of some of the Nano Gems. (See picture below).
Another sample was made in FS999 to get an accurate test of Nano Gems and enamels since the previous one became flawed. Seven different Thompson Enamels were applied to the piece, and it was fired seven different times. The Nano Gems were unchanged after seven flash firings with enamels at 1550°F / 843° C ( see below).
Nano Gems really do open a door full of possibilities; however through our testing we have concluded a few restrictions. When firing nano gems in silver clay, it is important to fire with an azure. All Nano Gems with the exception of Emerald Green can be fired in Magic Carbon. If you would like to fire Nano Gems in base metal clays, we highly recommend testing first. We hope this information comes useful to you in your next project with Nano Gems! Happy Making!
Annie Kilborn February 27, 2018