I have stated a number of times that the mixture used to make Prosser beads is "clay combined with ground glass." Actually, this is how glassy porcelain is made.

The mixture used for making Prosser beads includes feldspar. In the fusion of the beads, the feldspar melts and becomes glassy. The result is about the same, were actual ground glass included, but technically what I wrote was misstated.

In the interest of accuracy.

JDA.