A lightweight refractory material processed from high purity alumina-silica fibers. Withstands temperatures up to 2300 degrees F. Does not contain asbestos, however, kiln venting is necessary as this material does not burn off. An approved respiratory mask is recommended.
IMPORTANT: Read the material data sheet and use with due caution! http://edhoy.com/pdf/4822_482202_4822132_MSDS.pdf
I fuse a small strip of this between my glass layers in a cabochon to leave a space for the chain to go through. I just push out the material with a skewer after fusing.