Changes

Without scientific backing for crystals' physical properties, however, interest in them largely died out by the beginning of the 1980s. As William Jarvis of the National Council Against Health Fraud in Loma Linda, California, has noted, "As far as I know, there is no convincing published data to indicate that crystals have any efficacy in healing. The effects that are claimed are more in the realm of the metaphysical than the physical. They cannot really be measured, and can be readily understood as placebo effects. Until there is scientific documentation, these treatments should be presented only as medical experiments, not as valid medical therapy." Meanwhile, the Chiropractic Board of Examiners in Massachusetts has banned the use of crystals in chiropractic work in the state.

== References ==