Ask an experienced metal clay artist if diamonds can be co-fired in silver clay and most will advise against it. This is because it was something few dared and even fewer succeeded in doing. It was not a good bet.
In my 2005 article, Gemstones in Metal Clay, I warned that firing diamonds was a risky proposition. Diamonds have been known to disappear in the kiln, and torch firing often results in a cloudy stone. But now, with the help of activated carbon, diamonds and many other heat-sensitive stones can be safely co-fired in all types of metal clay.
In my updated Gemstones in Metal Clay article (click the title to download), you’ll learn about carbon firing and which stones can be carbon-fired sucessfully in metal clays. Heat-sensitive gemstones (those that darken or change colors when fired in metal clay) can often take hours of firing with no damage when protected in a bed of activated carbon, and they can withstand higher temperatures. Take the case of the Tanzanite CZ. When fired on a kiln shelf or embedded in fine silver clay, this stone can take no more than 10 minutes at 1110F before the color begins to change. But when the same stone was buried in activated carbon, it survived an amazing 16 hours at 1500F with no change in color or clarity!
I’ve created a video showing the making of my Diamond Burst Necklace. After firing several small diamonds in carbon, I needed to fire a larger one. I created the necklace in PMC PRO to document the test firing. The Antique Mold I used is called Mushroom Cap. I wet-set a 1/3 carat natural diamond and fired it in a firing box made with our exclusive No-Flake Firing Foil, and coconut carbon. The firing was a success and the diamond came out just as sparkling and clear as it went in! (I couldn’t have been happier! that diamond was appraised at $900!) After firing, I burnished the necklace and added an antique patina with Cool Tools Patina Gel. To remove the unwanted patina and add a satin finish, I used a coarse Mini-Fiber Wheel. I polished the front with a 400 grit 3M Polishing Paper.
I hope you will give diamonds a try with this wonderful method. Diamonds are more affordable than you may guess (unless of course you use a really big one!) and add scintillation and cachet like no other stone! Add beautiful distinction to your jewelry with diamonds.
Diane Rein January 15, 2011