There are two varieties of Jade, Jadeite and Nephrite. Nephrite is quite similar to Jadeite, but its colours are creamier and less translucent than Jadeite; Nephrite is the more commonly found variety. Jade may come in a variety of colours, green, blue, black, violet, white, yellow and a reddish and brownish variety. Each with its own slightly different use. The term jade is applied to two different metamorphic rocks that are made up of different silicate minerals: Nephrite consists of a microcrystaline interlocking fibrous matrix of the calcium, magnesium-iron rich amphibole mineral series tremolite - ferroactinolite. The higher the iron content the greener the colour. Jadeite is a sodium- and aluminium-rich pyroxene. The gem form of the mineral is a microcrystaline interlocking crystal matrix. The English word jade as well as the English word "jadeite" is derived from French l'ejade and Latin ilia and from the Spanish term piedra de ijada or "loin stone", from its reputed efficacy in curing ailments of the loins and kidneys. Nephrite is derived from lapis nephriticus, the Latin version of the Spanish piedra de ijada. The two minerals are both exquisite for the purposes that jade is put to task and are hard to distinguish from each other. Jadeite is almost never found in individual crystals and is composed of microscopic interlocking crystals that produce a very tough material. Nephrite is actually not a mineral, but a variety of the mineral actinolite. The nephrite variety is composed of fibrous crystals inter-twinned in a tough compact mass.
The toughness of jade is remarkable. It has a strength greater than steel and was put to work by many early civilizations for axes, knives and weapons. It was later that jade became a symbolic stone used in ornaments and other religious artifacts during the eons. During Neolithic times, the key known sources of nephrite jade in China for utilitarian and ceremonial jade items were the now depleted deposits in the Ningshao area in the Yangtze River Delta and in an area of the Liaoning province in Inner Mongolia. Jade was used to create many utilitarian and ceremonial objects, ranging from indoor decorative items to jade burial suits. Jade was considered the "imperial gem". From the earliest Chinese dynasties, the jade deposits in most use were from the region of Khotan in the Western Chinese province of Xinjiang. There, white and greenish nephrite jade is found in small quarries and as pebbles and boulders in the rivers flowing from the Kuen-Lun mountain range northward into the Takla-Makan desert area. River jade collection was concentrated in the Yarkand, the White Jade (Yurungkash) and Black Jade (Karakash) Rivers. From the Kingdom of Khotan, on the southern leg of the Silk Road, yearly tribute payments consisting of the most precious white jade were made to the Chinese imperial court and there transformed into objets d'art by skilled artisans, as jade was considered more valuable than gold or silver.
The Jainist temple of Kolanpak in the Nalgonda district, Andhra Pradesh, India is home to a 5-foot (1.5 m) high sculpture of Mahavira that is carved entirely out of jade. It is the largest sculpture made from a single jade rock in the world.
Nephrite jade in New Zealand is known as pounamu in the Maori language (often called "greenstone") which plays an important role in Maori culture. It is considered a taonga, or treasure, and therefore protected under the Treaty of Waitangi, and the exploitation of it is restricted and closely monitored. It is found only in the South Island of New Zealand, known as Te Wai Pounamu in Maori—"The [land of] Greenstone Water", or Te Wahi Pounamu—"The Place of Greenstone". Nephrite jewellery of Maori design is widely popular with locals and tourists, although some of the jade used for these is now imported from British Columbia and elsewhere.
Jade was a rare and valued material in pre-Columbian Mesoamerica. The only source from which the various cultures, such as the Olmec and Maya, could obtain jade was located in the Motagua River valley in Guatemala. Jade was largely an elite good, and was usually carved in a variety ways, whether serving as a medium upon which hieroglyphs were inscribed, or shaped into symbolic figurines. Generally, the material was highly symbolic, and it was often employed in the performance of rituals.