Gems and also crystal healing are kinds of alternative medicine technique that employs stones and crystals as healing tools. The practitioner places crystals on different parts of the body, often corresponding to chakras, or places crystals around the body in an attempt to construct an “energy grid”, which is purported to surround the client with healing energy. According to practitioners, when the stones are placed in the area of the chakras, the color of the stones may be chosen so as to correspond to the color which is said to be associated with the corresponding chakra. Stones are used at the feet to try to “ground” the individual, or held in the hands. Practitioners sometimes use crystal wands, which are placed near the receiver’s body, or near a certain ‘blocked’ chakra. Different cultures have used crystal healing over time, including the Hopi Native Americans of Arizona and Hawaiian islanders, some of whom continued to use it as of 1997. The Chinese have traditionally attributed healing powers to microcrystalline jade, and some other eastern cultures. Believe that emerald will strengthen the memory and increase intelligence There is no peer reviewed scientific evidence that crystal healing has any effect. It has been called a pseudoscience. Pleasant feelings or seeming successes of crystal healing can be attributed to the placebo effect, or the believers wanting it to be true and seeing only things that back that up; cognitive bias. Crystal healing techniques are also practiced on animals, although some veterinary organizations, such as the British Veterinary Association, have warned that these methods are not scientifically proven and thus could cause greater harm if not used in conjunction with conventional, effective medical care.