Uncut (left) and cut jadeite.—Runk/SchoenbergerGrant Heilman
Gem-quality silicate mineral in the pyroxene family that is one of the two forms of jade. Jadeite (imperial jade), sodium aluminum silicate (NaAlSiO), may contain impurities that give it a variety of colours: white, green, red, brown, and blue. The most highly prized variety is emerald green. Jadeite occurs only in metamorphic rocks, most often in those that have been subjected to the high pressures deep below the Earth's surface. The area around the city of Mogaung in northern Myanmar has long been the main source of gem-quality jadeite.