Small seized glass shards, generally, coloured, used for spotted couloring. Received that name for the thicker part of the corn flour that that is in fact wanted effect with this technique. On formal terms Granzioli are smalls pieces of glass, about the size of grains of rice that are used for decorate the main piece.
These little parts are hot stamped into the main piece obtaining a wrinkle effect.
Smaller sized granzioli are called Macie , whilst larger glass fragments are known