Probably the oddest idea I know of, is how an ancient piece of coloured glass can improve your health, the experts used word salad, simply using long and overly complex terms to suggest they know how things work, and the believers who don’t yet have this the spiritual lexicon, will simply say ‘I don’t know how it works, but it does.’ In this kind of case, I don’t know what’s worst, the people saying they know because they can make poorly supported arguments sound clever, or the sad cases who accept the bad arguments and cannot explain why they get a kick out of crystals. Interestingly, it doesn’t have to be old, natural, crystals, just fused glass with a nice colour works great on people who don’t know better, such as blue obsidian, commonly this is just a light blue glass, and is quite popular as a tumble-stone, which means many people are buying a machine smooth piece of glass mostly because it’s a nice colour. Popular shapes for such items include pyramids and spheres, that pseudo-experts claim help energise an environment, channelling cosmic energy, etc. However, there is nothing to the science-like claims, other than the placebo built up by a new age mystics, even if they refer to ancient cultures liking fancy looking pieces of old glass, such as the long historical use of jade in the Far-East, or ancient cultures having rituals which included them, such as the ancient Jewish high priest breastplate, which is said to of had twelve gems in it, to represent the twelve tribes of Israel.
Pointing out where other cultures, including ancient ones, use or used gemstones, doesn’t confirm that since they had them they must have thought of them as you think of them now, and even if they did, how does that prove anything, since each culture varied, and modern new age mysticism goes to the extreme of crystal based healing and meditation. To a Buddhist a crystal may prove a helpful thing to focus on, just as, for decoration and superstition a gem encrusted crown, in 12th century Europe, may convey a sense of power, but can we find anything near the magical ideas of the modern new age movement, apart from elements that often related to various primitive and ineffective practices, some continued through shamanism and esoteric beliefs. In essence, the practices of meditation and devotion with stones is a throwback belief, grounded more in thought reform than practicality, offering self-induced states of delusion, not genuine states that would be far more interesting, to critics it’s just collecting pebbles and carvings in the belief they have magical properties. The best thing you can say about the properties of crystals and minerals is that the spiritual/psychic claims cannot be utterly refuted, like fairies and Santa Claus, and one day science may shine some light on such topics, although, modern psychology explains much of it, and other fields of study expose the ignorance and wishful thinking of new age spirituality.