The person who made this video specializes in studying wireless radiation. He has also studied ionizing radiation, to a lesser degree. Here he places a Geiger counter over a popular pendant made of volcanic rock that many people wear to "protect themselves from EMF radiation" -- wireless frequencies, and possibly electromagnetic fields (EMF can stand for either). Background ionizing radiation (from radioactivity) is generally only a few counts per minute (e.g. 20), depending on where you are.