Late last year I was in a room with a very large lamp made of Himalayan salt. The lamp had a soft, peaceful glow that seemed to emanate on more than the visible spectrum. I felt calm, safe, unhurried, and peaceful in that room. Intrigued, I looked into the subject.
If various sources are correct, Himalayan salt is mined in the Himalayans; its origin is from an eons-old ocean that dried up into a huge salt bed, which was then submerged under tons of earth so that it compressed into a very hard form of salt. Because the salt was laid down so long ago, it is free of modern pollutants. Because it was from an ancient ocean, it has the range of trace elements and minerals that natural sea salts have. (As a side note, normal table salt has had all but the sodium chloride removed from it and thus has very little to recommend its use.)