There are two different minerals known as jade. They are “nephrite,” which is an amphibole, and “jadeite,” which is a pyroxene. Nephrite is the most common and widespread. It is formed of a mat of tightly interlocking fibers, creating a stone tougher than steel. It was used in China and New Zealand for tools and weapons due to its toughness. Its color varies with its composition dark green when iron-rich; cream colored when magnesium-rich. The term “jade” evolved from the Spanish piedra de ijada, meaning “loin stone,” a stone of similar appearance to nephrite brought from the New World by the Spanish, which was, in fact, jadeite.
There are two different textures that help distinguish nephrite from jadeite; nephrite appears fibrous or silky; jadeite commonly has a more sugary or granular texture. It has a bright glassy shine. Pure jadeite is white. Its other colors include green, colored by iron; lilac, colored by manganese and iron; and pink, brown, red, blue, black, orange, and yellow, colored by inclusions of other minerals. Emerald-green jadeite, colored by chromium, is called imperial jade. The latest classification of jadeite jade is; “A” jade (natural untreated); “B” jade (polymer treated); “C” jade (stained); “B” & “C” jade (polymer treated and stained).
For the Indians of Mexico, Central, and South America, jadeite was a symbol of water and the burgeoning of plant life. Known as chalchihuitil, it was more precious than gold. The Olmecs were the first Mesoamericans to discover and carved jade; perhaps 3,000 years ago. Across Mexico and Central America it was used in the most precious objects: masks, depictions of the gods, and ritual items. A piece of jade was placed in the mouth of a deceased nobleman which was believed to serve as his or her heart in the afterlife. Jade grave goods were essential for members of the nobility in most Mesoamerican cultures. When powdered and mixed with herbs, jadeite was used to treat fractured skulls and fevers, and to resurrect the dying. Mesoamerican jadeite principally came from sources in Guatemala and Costa Rica.
Myanmar is a major source of jadeite, and in particular imperial jade. Other sources are in Japan and California. Until the late 16th century, virtually all European jade was nephrite. When the Spanish reached Mexico, they discovered that the Aztecs prized a green stone that was similar in appearance to, and believed to be the same stone as, European jade. They were told by the Aztecs that this stone cured internal ailments, especially those of the liver, spleen, and kidneys. This stone was brought back to Europe, along with the belief in its healing powers. The jade from South America was believed to be the same as the Old World jade until 1863, when a Chinese carving was analyzed and discovered to be a different stone. The new stone was given the name jadeite, meaning derived from jade.
Jadeite and Nephrite can often be confused with agalmatolite, amazonite, aventurine, californite, chrysoprase, hydrogrossular garnet, pectolite, plasma, prase, prehnite, serpentine, emerald, smaragdite, smithsonite, and verdite