fossilesqueCrystals
blaue_FledermausNot to defend these things, I also don't think they work, but the simplest argument is that they work on a metaphysical frequency/energy/whatever, so a physical instrument wouldn't be able to detect it.
XtallllMany of them are also dangerously radioactive.
grueWait a minute, how radioactive? Better or worse than collecting old smoke detectors, Radioactive Boy Scout-style?