Electron Microprobe Analysis of Jade Reveals Exchange

Electron Microprobe Analysis of Jade Reveals Exchange

Monday, November 19, 2007

Keywords: sourcing, jade, nephrite, trade, electron microprobe analysis
Summary: Archaeologists have found the mineralogical equivalent of a "Made in Taiwan" label for jade earrings unearthed in Vietnam and the Philippines. There are actually two minerals that are commonly known as "jade." One is jadeite, a pyroxene mineral with a composition of NaAlSi2O6. The other is nephrite, which is a variety of actinolite, an amphibole with a composition of Ca2(Mg,Fe)5Si8O22(OH)2. The earrings are actually nephrite, and electron microprobe analysis of the earrings and nephrite sources has shown that many of them came from one source in eastern Taiwan. These findings have changed the picture of trade in the region.
Above: An earring made two millennia ago of Taiwan nephrite and found in Vietnam. Credit: Yoshiyuki Iizuka.
Read my comments on sourcing nephrite using electron microprobe analysis here and here.
Excerpt from ABC Science:
Jade Earrings Open Door on Ancient Trade
By Dani Cooper
Taiwan was at the centre of a one of the most extensive sea-based trade networks in the prehistoric world, new research shows.
The network, which traded in Taiwanese jade, has been uncovered after mineral analysis determined the source of jade used in two types of earring.
Lead researcher Hsiao-chun Hung, of the Australian National University in Canberra, says since the 1930s archaeologists have noticed two very specific styles of ancient jade earring common across Southeast Asia.
These are the three-pointed, so-called lingling-o earring, and the double-headed animal ear pendant.
Hung says mineral analysis of a number of these has shown most are made from Taiwanese jade.
Her finding overturns the long-held theory that the earrings originated in northern Vietnam and spread to the Philippines and Taiwan.
It also suggests, she says in the latest Proceedings of the National Academy of Sciences journal, the existence of a small group of highly skilled jade craftsmen who carried or acquired the jade from Taiwan. . .

To read the rest of the article, please visit the ABC Science website:
http://abc.net.au/science/articles/2007/11/20/2095026.htm
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Excerpt from Reuters:
Ancient Jade Study Sheds Light on Sea Trade
By Tan Ee Lyn
Over 100 ancient jade artifacts in museums across southeast Asia have been traced back to Taiwan, shedding new light on sea trade patterns dating back 5,000 years, researchers said.
Using X-ray spectrometers, the international team of scientists analyzed 144 jade ornaments dating from 3,000 BC to 500 AD and found that at least 116 originated from Fengtian in eastern Taiwan.
"The chemical composition of jade reveals its origin and ... their analysis determined the relative amounts of iron, magnesium, and silicon in the jade," the scientists wrote in a paper published in the latest issue of the Proceedings of the National Academy of Sciences.
"Based on elemental composition, 116 artifacts were identified as originating in Fengtian. The source of the others remains unknown."
Fengtian jade has a distinctive translucent green hue and black spots.
The 144 artifacts were unearthed in archaeological excavations in Taiwan, the Philippines, Malaysia, Vietnam, and Thailand. . .
"Fengtian jade was shipped to these workshops in southeast Asia, which dated from 500 BC to 100 AD. They were very small and they churned out these ornaments that were then exported to other places," said Hung, of the Australian National University in Canberra. . .

To read the rest of the article, please visit the Reuters website:
http://uk.reuters.com/article/scienceNews/idUKL192379920071119?rpc=401&
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Excerpt from Nature News:
Jade and Language Travelled Together
By Katharine Sanderson
Prehistoric purveyors of jade spread their trade from a single Taiwanese source throughout a huge area of Southeast Asia, possibly bringing Austronesian languages with them.
From as early as 3000 BC people from Southeast Asia used jade to make tools and ornaments. This later included ear pendants, such as a three-pointed jade ornament called a lingling-o. These ornaments have been found in southeastern Taiwan, and also all the way out to the Philippines, eastern Malaysia, southern Vietnam, central and southern Thailand, and parts of Cambodia.
Hsiao-Chun Hung, at the Australian National University in Canberra, and her colleagues took a close look at lingling-o and other pendants found in archaeological digs across Southeast Asia, to find out where they came from.
Rather than focus on the style and patterning on the ornaments, Hung used an electron probe microscope, which can work out the elemental composition of each sample without causing any damage. This is the first time that the technique has been used to look at jade, says Hung.
Her work shows that 116 of 144 jade ornaments from across the 3,000-kilometre-wide region came from the Fengtian jade deposit in eastern Taiwan. The Fengtian samples included incomplete ornaments and cast-off pieces of jade thought to come from the manufacturing process, which leads Hung to suggest that the jade was transported as a raw material. “This of course implies movement of people and technology,” says Hung. Her findings are published in Proceedings of the National Academy of Sciences. . .

To read the rest of the article, please visit the Nature News website:
http://www.nature.com/news/2007/071119/full/news.2007.268.html
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Excerpt from the New York Times:
Ear Pendants Reveal the Antiquity of Commerce in Jade
By Henry Fountain
Jade has been prized for thousands of years, and has been traded for nearly as long. The extent of the trading has been demonstrated by Hsiao-Chun Hung of the Australian National University and colleagues in a study of jade ornaments from Southeast Asia. . .
Archaeological evidence suggests that the jade was distributed as blanks. The researchers suggest that itinerant craftsmen may have traveled among the coastal lands, fashioning these decorative pendants for wealthy locals.
However the items were made, their distribution from one source across hundreds of miles of ocean represents one of the most extensive trading networks of a single mineral among ancient peoples.

To read the rest of the article, please visit the New York Times website:
http://www.nytimes.com/2007/11/20/science/20objade.html?_r=1&oref=slogin
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Excerpt from National Geographic News:
Jade Earrings Reveal Ancient SE Asian Trade Route
By Carolyn Barry
Jade jewelry found near ancient burial sites across Southeast Asia has revealed one of the largest marine trading networks of prehistoric times, a new study says.
Mineral analysis shows that most of nearly 150 sampled artifacts dated as far back as 3000 B.C. can be traced back to a single site in Taiwan. . .
This indicates that the small island supplied much of Southeast Asia with a unique variety of the semiprecious stone via a 1,800-mile (3,000-kilometer) trade route around the South China Sea. . .
The existence of such a vast trading network shows that these populations had developed sophisticated seafaring vessels and had extensive communication much earlier than previously believed. . .
Specifically, the team focused their study on two types of distinctive jade ornaments: three-pointed "lingling-o" earrings and two-headed animal pendants that were popular from 500 B.C. to A.D. 500.
Using high-powered scanning electron microscopes, the scientists measured the relative amounts of iron and magnesium and the presence of small specks of zinc chromite in the jade.
These chemical signatures showed that 116 artifacts found at 38 different locations originated from the Fengtian jade deposit in eastern Taiwan. . .
Most likely, these craftsmen exported the jade as a raw material and then manufactured it into jewelry locally, Bellmore said. "The jade comes from Taiwan, but a lot of artifacts are not made in Taiwan". . .

To read the rest of the article, please visit the National Geographic website:
http://news.nationalgeographic.com/news/2007/11/071120-jade-trade.html
Read my comments on sourcing nephrite using electron microprobe analysis here and here.

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