A clear, transparent form of quartz that has not been coloured by the presence of other minerals. The purestù of all quartzes, crystal is named from the Greek Krystallos (13th century) meaning ice. Because quartz transmits heat it is cool to touch and crystal was originally believed to have been ice that had lost its ability to melt. Quartz crystals have been used for religious purposes since ancient times when priests used them to render negative energy impotent, to destroy black magic and to dissolve enchantments and spells. Quartz is said to have been one of the stones used in the breastplate of the ancient high priest. Quartz crystals have been used extensively by many cultures for diagnostic healing. During the days of the old waysù, people as widely dispersed as Native American Indians, African tribes, Egyptians, Mayans, Aztecs, Australian Aborigines, Romans, Celts, Scots and Tibetan Buddhists relied on quartz crystals to recognize the origin of disease. Romans used crystals to reduce fevers and to relieve pain in medieval times they were held against the tongue to alleviate fever as well as diminish thirst. Numerous healing properties have been ascribed to quartz in general and rock crystal in particular since ancient times and it is, in fact, used more frequently today for healing and diagnosis than any other stone naturopaths, faith healers, Clairvoyant and psychic healers commonly use crystal.