Did some research on these tools. You can search for diamond beading tools on amazon and you will find these. Beware, what you find on amazon are cheap tools that are not good for jewelry work, but would probably work great for paper. When a diamond is set into prongs in a setting, a ring for example, the prongs are bent to grasp the diamond gem. The beading tool, rounds off the top of the prong. These are not punches but have round dimples in the tips. They can also be used to put the dimples in the setting around a gem. Goldsmiths use them for that purpose.
Thanks for introducing us to this tool as it is exactly what I have needed in my model work. I will be buying some of these.