Charmstone
A charmstone is a mineral specimen which certain prehistoric, historic or contemporary peoples invest with healing, mystical or paranormal powers. This belief has been part of several indigenous cultures for centuries, e.g., cintamani.  The mineral specimen may either be naturally occurring or honed from a natural stone; in some cases, the specimen may be entirely manufactured as in the case of certain Mayan pottery finds.  For example, the Miwok and Pomo tribes of Northern California have left thousands of charmstones in the bed of Tolay Lake in Sonoma County.  Charmstones are evidenced by the Shalagram and lingam in the Hindu tradition and by maban in the indigenous Australian tradition.  Jigme Lingpa in the Vajrayana tradition wrote a treatise on charmestone usage which Namkhai Norbu mentions. Charmstones were used in prehistoric Native American cermonies for broader spiritual purposes including securing of productive harvests.  Today it is becoming popular among certain countercultures within Western society such as the new age movement, but is regarded as baseless by scientists and medical professionals.

# Healing
Some crystal healers claim that each living organism has a "vibrational energy system," which includes chakras, electromagnetic fields around the body known as auras, subtle bodies and meridians. By using the appropriate crystals one can allegedly "tune" an energy system or rebalance energies, thus improving well-being due to the vibrations produced by the crystals, according to color, chemical composition, atomic structure and overall physical form.  Using the vibrations of the crystals a trained practitioner can allegedly move, absorb, focus, direct and diffuse energy within the body, using the structure of the crystal for the body to emulate. Crystal healing also allegedly gives the body a chance to relax, which may aid in the bodys natural abilities of the immune system.
The earliest records of crystal healing come from ancient Egypt. The Ebers papyrus states the medicinal uses of many different gems. Healing with crystals is also recorded in India's Ayurvedic records and in traditional Chinese medicine from around five thousand years ago. Several shamanistic cultures practice crystal healing, including the Inuit of Canada, which was adopted by New Age healers.
Various fictional works have used crystals as a focal point for magical spells; an idea probably founded on scrying-gems such as John Dee's shew stone. This, and similar, was used by magicians, fortune-tellers, etc. for one of two purposes; to co-ordinate the visionary power or to misdirect the attention of the customer.

# Criticism
Scientists, medical professionals, and skeptics consider crystal healing to be pseudoscientific, since there is no scientific evidence that healing can be achieved by 'crystal power'. The placebo effect, cognitive bias and memory biases are strong possible explanations for any examples of healing that occurs in the presence of a crystal. Even some crystal healing practitioners have cautioned that crystal healing should be used as a supplement to and not a replacement of conventional medicine.
It can also be classified as a pseudo-science under a number of Stephen Carey's criteria.  Carey explains that the "respectability" of science and scientific concepts comes from the experiments and the manner in which they are performed.  He goes on to assert that the difference between pseudo-science and science includes the "self-correction" of science, where  incorrect conjectures have been reversed by further investigation, and the publication and reversal of reviewed journals.  Thus far there are very few to no reviewed journals or published experiments regarding the use of crystal healing, further strengthening the argument for it as a pseudo-science.  Moreover, scientific findings are "open to revision" where seldom do the declarations of pseudo-sciences change, as illustrated with the old theory of the planets and sun revolving around the earth, whereas the claims of crystal healing are based on historical beliefs.