Tourmaline for health

My family made a trip to China recently. The tour guide took us to a small shop toward the end of the tour, as done to most Chinese tourist groups. The shop's sales pitch in this case is not as annoying as expected. In fact, I learned something new in her talk, particularly the part about tourmaline.

Tourmaline "is a crystal boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium". The Wikipedia page has a great deal of info about its physical properties, but not about its biological effect. Some people, presumably the Japanese initially, found that the far-infrared radiation it emits may be useful to certain health conditions. So far so good. From that point on, there's too much fanfare and exageration of its magic power, which I'll dismiss, as does this paper does.

But I'd like to point out one interesting feature of this "magic" mineral, which may or may not have medical effect: heating of body but not skin or air. This special heating achieved by far-infrared radiation differs from that of normal, infrared radiation (or other types of heating, such as convection) in that the latter also heats the skin, and air if not directly contacted. I wrapped a band containing this mineral on my wrist. About ten minutes later, I felt hot inside the wrist. I can imagine its potential use in niche cases such as when the patient needs heat but the skin can not take it for some reason. I sincerely hope a systematic study is done on these specific cases (so the research is more falsifiable, in Karl Popper's term, therefore more scientific), filtering out a large proportion of hype, and keeping the gem in people's verbal praise.