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Jade is an ornamental stone. The term jade is applied to two different metamorphic rocks that are made up of different silicate minerals. Nephrite jade consists of the calcium- and magnesium-rich amphibole mineral actinolite (aggregates of which also make up one form of asbestos). The rock called jadeitite consists almost entirely of jadeite, a sodium- and aluminium-rich pyroxene. The trade name Jadite is sometimes applied to translucent/opaque green glass.
The English word 'jade' is derived from the Spanish term piedra de ijada (first recorded in 1565) 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.1
Nephrite and jadeite were used by people from the prehistoric for similar purposes. Both are about the same hardness as quartz, and they are exceptionally tough. They are beautifully coloured and can be delicately shaped. Thus it was not until the 19th century that a French mineralogist determined that "jade" was in fact two different materials.
Among the earliest known jade artifacts excavated from prehistoric sites are simple ornaments with bead, button, and tubular shapes2. Additionally, jade was used for axe heads, knives, and other weapons. As metal-working technologies became available, the beauty of jade made it valuable for ornaments and decorative objects. Jade has a Mohs hardness of between 6.5 and 7.0,3 so it can be worked with quartz or garnet sand, and polished with bamboo or even ground jade.
Nephrite can be found in a creamy white form (known in China as "mutton fat" jade) as well as in a variety of green colours, whereas jadeitite shows more colour variations, including blue, lavender-mauve, pink, and emerald-green colours. Of the two, jadeite is rarer, documented in fewer than 12 places worldwide. Translucent emerald-green jadeitite is the most prized variety, both now and historically. As "quetzal" jade, bright green jadeitite from Guatemala was treasured by Mesoamerican cultures, and as "kingfisher" jade, vivid green rocks from Burma became the preferred stone of post-1800 Chinese imperial scholars and rulers. Burma (Myanmar) and Guatemala are the principal sources of modern gem jadeitite, and Canada of modern lapidary nephrite. Nephrite jade was used mostly in pre-1800 China as well as in New Zealand, the Pacific Coast and Atlantic Coasts of North America, Neolithic Europe, and south-east Asia. In addition to Mesoamerica, jadeitite was used by Neolithic Korean, Japanese and European cultures.
Jade is the official gemstone of British Columbia, where it is found in large deposits in the Lillooet and Cassiar regions. It is also the official gemstone of the state of Alaska, found particularly in the Kobuk area. A two ton block of jade sits outside the Anchorage Visitor’s Center in downtown Anchorage, Alaska, mined from near Kobuk and donated to the city as a showpiece. Jade is also the state gemstone of Wyoming, U.S.A.citations needed
The 2008 Summer Olympic medals have a ring of jade.
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History
Prehistoric and Historic China
In the long history of the art and culture of the enormous Chinese empire, jade has always had a very special significance, roughly comparable with that of gold and diamonds in the West. Jade was used not only for the finest objects and cult figures, but also in grave furnishings for high-ranking members of the imperial family.
Prehistoric and Early Historic Korea
The use of jade and other greenstone was a long-term tradition in Korea (c. 850 B.C. - A.D. 668). Jade is found in small numbers of pit-houses and burials. The craft production of small comma-shaped and tubular 'jades' using materials such as jade, microcline, jasper, etc in southern Korea originates from the Middle Mumun Pottery Period (c. 850-550 B.C.)4. Comma-shaped jades are found on some of the gold crowns of Silla royalty (c. A.D. 300/400-668) and sumptuous elite burials of the Korean Three Kingdoms. After the state of Silla united the Korean Peninsula in A.D. 668, the widespread popularisation of death rituals related to Buddhism resulted in the decline of the use of jade in burials as prestige mortuary goods.
Māori
Nephrite jade in New Zealand is known as pounamu in the Māori language, playing an important role in Māori 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 Māori - "The [land of] Greenstone Water", or Te Wahi Pounamu - "The Place of Greenstone".
Tools, weapons and ornaments were made of it; in particular adzes, the 'mere' (short club), and the Hei-tiki (neck pendant). These were believed to have their own mana, handed down as valuable heirlooms, and often given as gifts to seal important agreements.
One name used for nephrite jade in New Zealand English is "greenstone." While widely used to describe the material used for jewellery items made for the tourist trade, it is a misnomer and simply engenders confusion. The stone should be correctly referred to as "nephrite" or "nephrite jade". 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.5
Mesoamerica
Jade was a rare and valued material in pre-Columbian Mesoamerica. The only source from which the various indigenous cultures, such as the Olmec and Maya, for example, 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 ideological practices and rituals.
Today, Guatemala produces jadeite in a variety of colours, ranging from soft translucent lilac, blue, green, yellow, and black. It is also the source of new colours, including "rainbow jade" and the unique "Galactic Gold," a black jadeite with natural incrustations of gold, silver and platinum.6
Other names
Besides the terms already mentioned, jadeite and nephrite are sometimes referred to by the following:
Jadeite
Agate verdâtre, Feitsui, Jadeit, Jadeita, Natronjadeit, Yunnan Jade, Yu-stone, Sinkiang jade.
Nephrite
Aotea, Axe-stone, B.C. Jade, Beilstein, British Columbian Jade, Canadian Jade, Dushan Jade, Nanyang Jade, Du Jade, Henan Yu, Grave Jade, Kidney Stone, Lapis Nephriticus, Nephrit, Nephrita, Nephrite (of Werner), New Zealand Greenstone, New Zealand Jade, Siberian Jade, Spinach Jade, Talcum Nephriticus, Tomb Jade.
Faux jade
Many minerals are sold as jade. Some of these are: serpentine (also bowenite), carnelian, aventurine quartz, glass, grossularite, Vesuvianite, soapstone (and other steatites such as shoushan stone) and recently, Australian chrysoprase. "Korean jade," "Suzhou jade," "Styrian jade," "Olive jade", and "New jade" are all really serpentine; "Transvaal jade" or "African jade" is grossularite; "Peace jade" is a mixture of serpentine, stichtite, and quartz; "Mountain jade" is dyed dolomite marble.
Enhancement
Jade may be enhanced (sometimes called "stabilized"). There are three main methods, sometimes referred to as the ABC Treatment System:
- Type A jadeite has not been treated in any way except surface waxing.
- Type B treatment involves exposing a promising but stained piece of jadeite to chemical bleaches and/or acids and impregnating it with a clear polymer resin. This results in a significant improvement of transparency and colour of the material. Currently, infrared spectroscopy is the most accurate test for the detection of polymer in jadeite.
- Type C jade has been artificially stained or dyed. The red colour of Red jade can be enhanced with heat. The effects are somewhat uncontrollable and may result in a dull brown. In any case, translucency is usually lost.
- B+C jade is a combination of B and C: it has been both artificially dyed AND impregnated.
- Type D jade refers to a composite stone such as a doublet comprising a jade top with a plastic backing.7
See also
- Jade burial suit
- Mumun Pottery Period, the time in Korea when jade ornament production began
- Heavenly Horse Tomb, a Silla royal tomb in Korea with jade artifacts.
- Pounamu
References
- ^ Easby, Elizabeth Kennedy. Pre-Columbian Jade from Costa Rica. (1968). André Emmerich Inc., New York
- ^ Liu, Li. The Products of Minds as Well as Hands: Production of Prestige Goods in Neolithic and Early State Periods of China. Asian Perspectives 42(1):1-40, 2003, pg 2.
- ^ http://www.orionsgemz.com/Mohs.html Orionsgemz.com Retrieved on 06-01-07
- ^ Bale, Martin T. and Ko, Min-jung. Craft Production and Social Change in Mumun Pottery Period Korea. Asian Perspectives 45(2):159-187, 2006.
- ^ Salt, Donn, 1992, Stone, Bone and Jade - 24 New Zealand Artists, David Bateman Ltd, Auckland.
- ^ Mesoamerican Jade
- ^ http://www.ssef-alumni.org/pdf/newsletter_3.pdf
- Scott-Clark, Cathy and Levy, Adrian. (2002) The Stone of Heaven: Unearthing the Secret History of Imperial Green Jade. ISBN 0316525960
Further reading
- Laufer, Berthold, 1912, Jade: A Study in Chinese Archeology & Religion, Reprint: Dover Publications, New York. 1974.
- Rawson, Jessica, 1975, Chinese Jade Throughout the Ages, London: Albert Saifer, ISBN 0-87556-754-1
- Dushan Jade (Du Jade)
- Jadeite sources in Mesoamerica (PDF)
- Between hell and the Stone of Heaven: Guardian article on Jade Mining in Burma
- Old Chinese Jades: Real or Fake?
- BOOK REVIEW, The Stone of Heaven: The Secret History of Imperial Green Jade by Adrian Levy and Cathy Scott-Clark
External links
- The British Museum - 7,000 years of Chinese jade
- Jade and the Chinese
- How To Tell Fake Jade
- Incarnations of Jade: Getting What You Pay For
- Maya Jade
- Jade: Chinese Stone of Heaven
- mindat.org
- Jade in Canada
- Chinese Jade
- "Jade in British Columbia table", BC Govt MINFILE summary of jade showings and producers
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- This page was last modified on 1 December 2008, at 19:11.
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