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What is Jade?


Jadeite and nephrite are the materials that have been collectively known as "jade" for thousands of years.




What is Jade?



"Jade" is a cultural term used for a very durable material that has been fashioned into tools, sculptures, jewelry, gemstones, and other objects for over 5,000 years. It was first used to manufacture ax heads, weapons, scraping and hammering tools because of its toughness.

Then, because some specimens had beautiful color and polished to a brilliant luster, people started to use it as gems, talismans, and ornamental objects. Although most people who think of jade imagine a beautiful green gem, the material occurs in a wide variety of colors that include green, white, lavender, yellow, blue, black, red, orange, and gray.


Are All Jades the Same?



Originally, all jade objects were thought to be made from the same material. However, in 1863 a Frenchman, Alexis Damour, discovered that people were using the word "jade" for two different minerals: jadeite and nephrite.

Because these two materials are so difficult to distinguish without expertise and equipment, and because the word "jade" is so entrenched in common language, the name "jade" is still widely used across many industries and academic disciplines.

In this article, the word "jade" will be used for undifferentiated materials. "Jadeite" or "nephrite" will be used when the difference between the two materials is known and important. (The word "nephrite" is also an imprecise term. It is used for materials composed of the minerals actinolite and tremolite.)


Jadeite, Nephrite, and Science



Jadeite and nephrite have distinctly different mineral compositions. Jadeite is an aluminum-rich pyroxene, while nephrite is a magnesium-rich amphibole.

However, the two minerals have very similar physical properties in the eye of the average person. Trained observers who do not have a lot of experience are unable to reliably differentiate them without mineral testing equipment. This is why jadeite and nephrite were not properly distinguished by scientists until 1863.


Physical Properties of Jadeite and Nephrite

 

Jadeite

Nephrite

Chemical Classification silicate - pyroxene silicate - amphibole
Color usually various shades of white to dark green, sometimes gray, pink, lilac, red, blue, yellow, orange, black, colored by impurities usually ranges in color between white, cream and dark green
Streak colorless colorless
Luster vitreous to sugary vitreous, silky, waxy
Diaphaneity translucent translucent
Cleavage usually not seen because of a small grain size - splintery fracture prismatic but usually not seen because of a small grain size - splintery fracture
Mohs Hardness 6.5 to 7 5 to 6
Specific Gravity 3.3 to 3.5 3.0 to 3.3
Diagnostic Properties color, toughness, hardness, specific gravity color, toughness, hardness, specific gravity
Chemical Composition NaAlSi2O6 or Na(Al,Fe3+)Si2O6 Ca2(Mg,Fe)5Si8O22(OH)2 
Crystal System monoclinic monoclinic
Uses jewelry, ornaments, tools, weapons, semi-precious stones jewelry, ornaments, tools, weapons, semi-precious stones


Jadeite, Nephrite and Artisans



China has been the leading producer of jade objects for over 5,000 years. A few hundred years ago, master Chinese craftsmen who worked with jade daily recognized that some of the jade obtained from Burma (now the Union of Myanmar) was different. It was harder, worked easier and produced a higher luster upon polishing. It gradually became the form of jade preferred by Chinese artisans and the jade most highly prized by the Chinese people. They realized this long before scientists differentiated jadeite and nephrite in 1863.

The Burmese jade - jadeite - was slightly harder and produced a higher polish. Unknowingly, they had distinguished jadeite from nephrite and appreciated it enough to pay premium prices for jadeite. However, they didn't have the knowledge and equipment of chemistry and crystallography to distinguish them in a formal way.

Rarely, the Chinese craftsmen encountered fine-grained jadeite with a bright translucence and a rich, uniform green color. This beautiful material was given the name "Imperial Jade" and regarded as the stone of highest quality. At that time in China, ownership of Imperial Jade was reserved only for the Emperor. Now, anyone who can afford it can own Imperial Jade. The best specimens can cost more than high-quality diamonds.


Other Materials Confused With Jade



A number of lower-value materials are also confused with jade. Green quartz, amazonite, chrysoprase, jasper, serpentine, aventurine, grossularite garnet and synthetic or imitation materials can be knowingly or unknowingly used in place of jade. These sometimes enter the marketplace without distinction. All of these materials can have a color, luster and translucence that is very similar to jade - so similar that the average person is unable to recognize them.

Dyes, bleaches, heat treatments, and other procedures are sometimes used to enhance the color and luster of jadeite, nephrite, or other materials to give them the appearance of the finest jade. These treatments can usually be detected in a careful examination by an experienced person using a microscope, hand lens, or ultraviolet light. The average person is unable to recognize them. Sellers have an ethical obligation to accurately identify the material that they are selling and reveal any treatment that has been applied.

The caution to buyers is this: If you are spending serious money for a jade object, be sure that you are buying from a knowledgeable and trusted dealer. If you don't know what you are buying, then you should pay no more for jade than you would pay for the same object made from a material with no intrinsic value.


Early Use of Jade in Tools



People have used jade for about 7,000 years. The earliest objects made from jade were most likely tools instead of gemstones. Jade is a very hard material and more important for use as a tool because it is extremely tough and breaks to form sharp edges.

  Mayan Ax Head
Mayan ax head made from jade
A reproduction of a Mayan or Aztec ax head. Photo copyright by iStockPhoto and Stacy Brogan.

"Toughness" is the ability of a material to resist fracturing when subjected to stress. "Hardness" is the ability of a material to resist abrasion. Early toolmakers took advantage of these properties of jade and formed it into cutting tools and weapons. It was used to make axes, projectile points, knives, scrapers and other sharp objects for cutting.


Use of Jade as a Gemstone



Jade is a durable, colorful material that can be worked into shapes and given a high polish. These properties make it a very desirable gemstone. Jade has been used to make a variety of jewelry items such as pendants, necklaces, rings, bracelets, earrings, beads, and other items.

These jewelry items are often made of solid jade, combined with other gems, or placed in settings made from gold, silver, or other precious metals. In addition to jewelry, jade is used to make small sculptures, ornaments, religious art, and small functional objects.


Geography of Jade



Most people immediately think of China as the source of jade and jade objects. Although China is the most important source for mined nephrite and the most important manufacturer of jade objects, the material is not unique to that country.

Jade has been used to make tools, weapons and important ornamental objects in Asia, Europe, Australia, the Americas, and numerous Pacific islands. In all of these locations, people held jade in highest esteem and used it to make religious art or ornaments for their rulers. None of these ancient cultures had contact with one another, yet they all independently used jade for many of their most sacred and important objects. Such is the appeal of jade.


Geologic Occurrence and Jade Prospecting



Jadeite and nephrite are minerals that form through metamorphism. They are mostly found in rocks associated with subduction zones. This places most jadeite and nephrite deposits along the margins of current or geologically ancient convergent boundaries involving oceanic lithosphere.

Jadeite is typically found in rocks that have a higher pressure origin than nephrite. This normally causes a geographic separation of jadeite and nephrite deposits.

From ancient times, most of the prospecting for jade has been done in the steeper parts of drainage basins where pebble- to boulder-size pieces of rocks are found in stream valleys. Boulders and pebbles of jade normally have a brown weathering rind that hides their inner beauty and potential value.

Prospectors search these valleys looking for jade boulders. Small windows are often cut into the boulders in the field to assess the material's quality and to determine if it is worth the labor of transport. Today, jade prospectors often scour the stream valleys, tag the jade boulders and hire a helicopter with a basket on a cable to fly in and retrieve the heavy jade boulders. One nice boulder can be worth tens of thousands of dollars or more in rough form.

Some jade is also mined from ancient conglomerates, and some is mined from ophiolite exposures. The ophiolites are a metamorphosed rock of ancient subduction zones, now exposed at the surface by faulting or uplift followed by exhumation by weathering.


Social Importance of Jade



In the United States and Europe, diamonds, rubies, sapphires, emeralds, opals, garnets and a few other gems are much more popular than jade. Jade is not thought to be as precious in these regions as it is in China.

The Chinese have a much higher regard for jade than any other people. For thousands of years, jade has been the most popular gemstone in China. Chinese emperors desired excellent specimens of jade, and they traded or waged war with distant people to acquire them.

In China, gifts made from jade are given at almost every important station in life, such as birthdays, anniversaries, marriages and other celebrations. It is also a commonly used material for producing religious art. China is the country where the importance of jade is the highest.


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  Green Jadeite Buttons
Green jadeite buttons
Hand-made, antique Chinese jadeite buttons showing the typical color range of high-quality green jadeite. The jadeite in these buttons was most likely mined in Burma (the Union of Myanmar today). This photo was taken by Gregory Phillips and is distributed under a GNU Free Documentation License.


  Green Nephrite Jade Pendant
Green nephrite jade pendant
A pendant made from a green nephrite known in New Zealand as "Maori Green Stone" or "Maori Jade." Photo copyright by iStockPhoto and Steve Patterson.

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Mayan jadeite
Hand-made Mayan jadeite pectoral from the Mayan Classic period. This photo was taken by John Hill and is distributed under a GNU Free Documentation License.

  Jade Dragon
Jade dragon
Hand-made jade dragon from the Western Han Dynasty (202 BC - 9 AD). This photo was taken by Snowyowls and is distributed under a Creative Commons Attribution ShareAlike 2.5 License.

  Light Green Nephrite Pendant
Light green nephrite pendant
A pendant in the shape of a flat disk made from a light green nephrite. Photo copyright by iStockPhoto and Trudy Karl.

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British Columbia jade cabochons
A pair of translucent cabochons cut from bright green British Columbia nephrite jade. Approximately 10 x 12 millimeters in size.

  Jade Dice
Jade dice
A pair of jade dice made from British Columbia nephrite.

  Maw Sit Sit
maw sit sit
Maw sit sit is a rock composed of jadeite, albite and kosmochlor (a mineral related to jadeite). It has a bright chrome green color and accepts a bright polish and for those reasons it is used as a gemstone. The rock was first discovered in 1963 near the village of Maw Sit Sit in northwestern Burma in the foothills of the Himalayas. This is the only location where it has been discovered to date. It is used to cut cabochons and small sculptures. Because of its rarity and low production it is rarely seen in jewelry.

  Green Jadeite - Alluvial Boulder
Green jadeite boulder
An alluvial boulder of green jadeite with a brown weathering rind from nothern Burma. This boulder is about 6 centimeters across. Photo by James St. John, used here under a Creative Commons License.

 Lavender Jadeite - Alluvial Boulder
Lavender jadeite boulder
An alluvial boulder of lavender jadeite with a brown weathering rind from nothern Burma. This boulder is about 18 centimeters across. Photo by James St. John, used here under a Creative Commons License.


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