Rocks in PMC?
by PMC Connection

Item# rocks

Product Description


Most of the colored gemstones, especially those below 7 on the Mohs scale, cannot withstand the temperature needed to fire PMC Silver or PMC Gold. Typically these stones have natural inclusions (unless they are a perfect stone). The inclusions in most natural stones have a different rate of expansion than the surrounding material. When you heat these stones, the different rates of expansion can result in cracks or splitting of the stone. Perfect stones do not have this difficulty.

Traditional gemstones, however, are not the only material which you can include with PMC+. After completing our initial testing of gemstones for use with PMC+, we turned our attention to other stones: river rocks, driveway stones and those great rocks you pick up while hiking on vacation. I got this idea in Japan while studying with Hitoshi Araki, Master Craftsman at Aida. The artists at Aida's studios have been using this type of material successfully and having great fun.

Many of these are ignacious rocks such as granite. Surprisingly, when fired they not only withstand the heat, they also can turn colors. Many have red iron oxide, which make a handsome stone when fired.

So start collecting interesting rocks and place them in your kiln. Fire at 1650o F for 10 minutes, using a slow ramp up to maximum temperature and a slow cool down period. Make sure that the stones are covered with a fiber blanket so that if they explode, they will not damage the inside of the kiln.

See what treasures you might find. This would be a great project for kids, camps, schools or as a sentimental keepsake from a special trip.


Natural stones frequently change color as a result of firing. For example, a purple amethyst may become a dull white after firing. Be careful!!! If a stone is expensive or precious to you, consider using it in a bezel setting or a special snap fit setting available through PMC Connection. For the brave of heart, however, experimenting can be really fun.

View Precious Metal Clay "how to" Video Series

U.S.A. Shipments only.
The minimum order is $25.
$6.60 U.S. Priority Mail shipping & handling.
Additional shipping charges, for items over one pound.

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Northern California
Hidden Valley Lake, CA 95467

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