Monday, September 17, 2012

How Jade Forms

Satellite image showing Yutien at the southern edge of the Talka-Makan
desert and the Kunlun Mountain chain with Mountain Jade deposits.
Photo credit: Friends of Jade
by Angela Magnotti Andrews

Though there is some mystery involved in the formation of jade, many geologists believe that both types of jade form primarily along subduction zones. A subduction zone is an area where one tectonic plate sinks beneath another one, setting off an earthquake.

These subduction zones are hailed by most geologists as the birthplace of looming volcanoes. It is believed that the same heat and pressure that forge the fiery furnaces are also responsible for the formation of nephrite and jadeite jade.

The force of this type of collision often causes rocks to shatter, opening small cracks into which chemical-rich thermal water flows from beneath the earth. Thermal water infused with all the right minerals and elements required to form jade are driven toward these newly formed fissures by heat and high pressures from below. As the water flows through the cracks and begins to cool, it leaves behind layer after layer of microcrystals of jadeite or nephrite which eventually completely fills in the chasm.

When the plates shift once again, either a week, a month, or even years later, the same crack, or a new one nearby opens up, repeating the same process all over again. For some of the huge deposits of jade to have formed by this process, it would have required a substantial number of earthquakes. Dr. George Harlow, jade specialist at the American Museum of Natural History, postulates that it would take millions of earthquakes to make a large deposit, such as the one most recently discovered in Guatemala.

While this theory holds much water in the field of jade formation (pun intended), there is some evidence that there are different geological processes responsible for different types of jade in different regions. This warrants further research and a followup article at a later time.

Read about the Composition of Jade.
BIBLIOGRAPHY

1. Harlow, George. "Jade." American Museum of Natural History: Ology. Accessed September 14, 2012. http://ology.amnh.org/explore/ology/earth/?pop=29462#http://www.amnh.org/ology/features/jade.
2. Jie, Ma Wen. "How Jade the Mineral Formed." eHow. Accessed September 14, 2012. http://www.ehow.com/about_6707397_jade-mineral-formed.html.
3. "Mesoamerican Jade." Authentic Maya. Last updated January 28, 2011. http://www.authenticmaya.com/Jade.htm.

*Clip art courtesy of The Graphics Fairy

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