jade

jade common name for either of two minerals used as gems. The rarer variety of jade is jadeite, a sodium aluminum silicate, NaAl(SiO ₃ ) ₂ , usually white or green in color; the green variety is the more valuable. The commoner and less costly variety of jade is nephrite, a calcium magnesium iron silicate of varying composition, white to dark green in color. Jade has been prized by the Chinese and Japanese, as well as by pre-Colombian Mesoamerican peoples, as the most precious of all gems. The Chinese in particular are known for the objets d'art they carve from it, and they traditionally associated it with the five cardinal virtues: charity, modesty, courage, justice, and wisdom; they also attributed healing powers to it. It was much used for implements by ancient peoples, especially in Mexico, Switzerland, France, Greece, Egypt, Asia Minor, and New Zealand. Jadeite is found in upper Myanmar, in Japan, and in Guatemala; nephrite in New Zealand, Turkistan, Siberia, China, Silesia, Wyoming, California, and British Columbia.

Bibliography: See S. C. Nott, Chinese Jade throughout the Ages (2d ed. 1962); R. Gump, Jade (1962); J. M. Hartman, Chinese Jade of Five Centuries (1969, repr. 1987); G. Wills, Jade of the East (1972); A. Levy and C. Scott-Clark, The Stone of Heaven (2002).

jade Semi-precious silicate mineral of two major types: jadeite, which is often translucent; and nephrite, which has a waxy quality. Both types are extremely hard. Jade is found mainly in Burma and comes in many colours, most commonly green and white. Hardness 5–6; r.d. 3–3.4.

jade See JADEITE.