This is an example of frit decoration that’s both twisted and manipulated with pincers. It begins by rolling a soft white glass bubble slowly over broken pieces of colored glass and, in this case, aventurine. The glass sticks. After reheating and marvering, the surface becomes smooth. The twist is begun by marvering in place. The friction creates torque that twists the bubble. The end is held with the tool, the blowpipe is turned, and the twist is made very tight. After reheating, the pincers gouge the glass and twist it to create the swirling effect. With more reheating and marvering, the surface can be made smooth again. The visual effect, however, remains. Now the glassblowing can begin. The glass is inflated gradually, rolled on the marver to inhibit the increase in size. The goal is to make an even-walled bubble. As in all glassblowing procedures, a constriction is formed between
the blowpipe and the bubble. After cooling, it can be seen that the aventurine and the true colors come out.