These are Fuse Master High Temperature Lead Free Enamels.

They mature at 1450°-1500°F (788°-816°C). A lead free series of inter-mixable opaque enamels.  May be blended to achieve a complete
spectrum of tones with a basic stock of colors. Vibrant colors are retained at the 1450°-1500°F temperatures needed for fusing. Powder
form. Easy to mix with a variety of mediums or Gum Arabic. Or for lampworking, you can sprinkle it, sift it, or roll your bead in it, what ever you
can think of!