Jadeite
Colors: White, green, yellow, red, orange, lavender, black and brown
R.I.: l.66 - l.68
Durability: Tough
S.G.: 3.30 - 3.38
Treatment: Dyeing
Hardness: 6 1/2 - 7
Availability: Some colors meet demand; others are very rare
Localities: Myanmar (Burma)
Price: Low to very expensive
Common shapes: Cabochons in oval, round, navette, etc. Some carved
Jade is a confusing term since it is used to refer to two different gem materials. The two jades, jadeite and nephrite, can be somewhat similar in appearance, so the confusion persists.
Jadeite was first imported into China in 1784 from Burma. Up to this time the jade used in China was nephrite jade. Jadeite is found in a few places in the world, but the only commercially mined deposit is in Burma. Burmese jade is another name for jadeite.
Mayans in Mexico and Guatemala had jadeite weapons and tools hundreds of years before the Chinese first saw the material. The Central American source was just recently discovered in Guatemala. If someone's skull can be broken with jadeite it certainly makes a durable jewelry stone!
The colors of jadeite vary from an interesting gray to the most intense green. Yellow to gold, pink to blue lavenders, rusty reds, light to dark greens, pure white, brown, and black are all jadeite colors. Many pieces show more than one of these colors.
As in other gem materials, the intensity of the color is the most important factor in judging quality. Transparency is also critical in valuing jadeite; the finest jadeite is semi-transparent, the lower qualities are opaque. Evenness of color is important for pieces of jade cut to display a single shade. There are also some very attractive patterns and variations of color which are also highly valued. The Chinese have names for many of these patterns, such as moss-in-snow.
Jadeite must be examined with a microscope to see if it has any internal fractures, these would reduce its value. If the jadeite is carved, the quality of the carving would be an important value factor. Evenness of cutting and polish are considerations in cabochon material. Evaluating a piece of jadeite is a complex process!
The most expensive jadeite is called "Imperial jade," which is an intense medium green color, semi-transparent, and even in color. A fine piece will have no internal fractures. Your chances of seeing a piece of fine Imperial jadeite are not great unless you really have time to look or are extremely lucky! Imperial jade is breath-taking; it has an inner glow unequaled by other stones. The price? very high!
What are you likely to find in fine quality jadeite? "Apple green" is a term often used to describe fine green jade that does not quite have the intensity of color or the transparency of the Imperial. It is still in the very expensive price range for a good size piece. Some times jadeite is cut into very thin pieces to enhance the translucency. Some times intense green portions of color will be in an otherwise white piece of jadeite; this is "moss in snow".
Fine lavender jadeite is very rare and can be priced in the expensive to very expensive range. Lavender jade may range from a pastel blue violet to a pastel pink violet. Saturation of color, evenness of color, and translucency are the factors to consider in lavender jade.
Other colors of jadeite will cost quite a bit less than the fine greens and lavenders. Color saturation, evenness of color and translucency are still the primary value factors.
Lesser qualities of jadeite can be quite unique. Pieces that are multi-colored and carved can be very affordable as well as interesting. Buy what you find as beautiful, particularly in carvings.
Frequently jadeite is dyed green or lavender. A knowledgeable seller is important when you are buying jadeite. Most dyed jadeite does not look quite right. If you are sold jadeite as natural in color, have the seller write on the sales slip that color is natural.
Jadeite is often sold by the piece rather than by carat weight as other gemstones are.
Nephrite Jade
Colors: Greens, white, yellow, brown, and black
R.I.: l.60 - l.64
Durability: Very tough
S.G.: 2.90 - 3.02
Treatment: None known
Hardness: 6 - 6 1/2
Availability: Sufficient supply
Localities: Taiwan, New Zealand, Russia and Alaska Prices: Low to very expensive
Common shapes: Cabochons of all shapes and beads
Nephrite jade is not as flashy as its cousin, jadeite; nevertheless this is the true jade of ancient China. Nephrite jade was imported into China over three thousand years ago and was the most prized of all Chinese possession. It too was used for tools, utensils, religious articles and as a jewelry stone. Nephrite weapons were also used by the Maoris in New Zealand. The fibrous structure of nephrite is very densely packed and as a result it is the "super skull crusher" gemstone. In spite of its low hardness, it is considered the toughest gem material.
The ancient Chinese highly valued the translucent creamy white nephrite which is called "mutton fat" jade. Today green nephrite is commonly available. "Spinach" jade is an descriptive term for much of the nephrite available; it may also be called "Taiwan jade"; it has a dark cooked spinach color. Fine nephrite in a bright yellowish green color is found in Russia; it has distinctive small black inclusions. Brightness of color and translucency are the quality factors to consider when buying nephrite. Nephrite jade falls into the low (and sometimes, moderate) price range; it may be sold by the piece rather that the carat.
Jade derived its name from the Spanish "piedras de ijada" which translates to "stone of the loins;" jade was thought to be a healing stone for kidney ailments. The Greek word "nephros" means "kidney." Rough nephrite jade boulders resembled kidneys.
About the Author
Sondra Francis has scoured every major colored gemstone market in the world since 1978. She was a charter member of the American Gemstone Association and served as a board member. She was a founding member of the International Colored Gemstone Association. A true gem lover, Sondra has marketed her treasures on the wholesale and retail markets.
Acknowledgments
A special thanks to Pam Dulgar, Alex Edwards, Cheryl Kremkow, Kate Kirby, Helen Mitchell, Carol Morgan Page, David Pond, Elaine Proffitt, and Ray Zajicek for their help.
Photographs: Bart Curren and ICA Gembureau ; Alex Edwards, Pearl Sales Institute ; David Dikinis
© Copyright 1996 - 2009, The Ganoksin Project
Monday, May 11, 2009
Jadeite Jade Grade and Jadeite Jade Treatment
Jadeite Jade Grade and Jadeite Jade Treatment
The value of Jadeite jade & how does treatment affects its value
Some will buy precious stone as an investment, for example, diamond. Jadeite jade is proved to be more profitable in these years. The price of jadeite jade rises about 100% to 50% per year.
But those can be looked as estate are only all natural jadeite jade, which is called A type jadeite jade. If the jadeite jade is treated, it can only act as an ordinary accessory or ordinary product, no longer a precious stone, because its texture is damaged and durability is greatly decreased. After it has been worn for a certain period of time, irregular tension micro-cracks will appear.
It is the reason why the price of all natural jadeite jade is far higher than treated ones, which is the difference between precious stone and ordinary accessory.
If you want to buy jade as investment or buy a real precious stone, remember to choose A type jadeite jade.
What are A type jadeite jade, B type, C type and so on?
A type jadeite jade: all natural jadeite, without any treatment. This type of jadeite jade can be bought as a real precious stone or investment.
B type jadeite jade: the natural jade is soaked in a mixed strong acid solution. Next, soak it in epoxy resin mixed with hardener. Then take it out and heat it to harden it. This kind of treatment can improve the color and transparency of the jade. But its texture is damaged and durability is greatly decreased.
Be aware that B type jadeite jade can also be called "natural color jadeite jade", because it is not dyed, its color is really natural. Ask the seller "is it soaked in acid solution?" as an additional question to confirm the jade you buy is an A type one.
C type jadeite jade: colored or dyed jade.
B+C type jadeite jade: the jade is dyed after acid-treated and resin-filled, which results in beautiful color and great transparency. But the color is not natural and the durability is greatly decreased.
D type jadeite jade: this kind is not real jadeite jade. It is another kind of jade or stone but looks like jadeite jade. It pretends to be jadeite jade because jadeite jade is the most precious and expensive one in the jade-like minerals.
Identification of A type, B type, C type, and B+C type jadeite jade
Some experienced craftsmen and traders can examine jadeite jade with naked eyes, by its color and luster. To consumers, the best way to judge a piece of jadeite jade is to ask for an identification certificate by a testing centre. In Chinese testing labs, A type jade will be marked as A-Jade in the identification result. Click to See Our Sample Certificate
As we know, Chinese people consume a lot of jadeite jade. Jadeite jade is the most popular gemstone in China. Correspondingly, high-tech instruments and methods are invented to test jade types in mainland China, HongKong, and Taiwan. For example, they will use magnifying lens, ultraviolet fluorescence analysis, microscope, infrared spectroscope, visible light spectroscope, ultraviolet lamp, so on and so forth. And judge from optic character, refractive index, absorption spectrum, and so on.
The value of Jadeite jade & how does treatment affects its value
Some will buy precious stone as an investment, for example, diamond. Jadeite jade is proved to be more profitable in these years. The price of jadeite jade rises about 100% to 50% per year.
But those can be looked as estate are only all natural jadeite jade, which is called A type jadeite jade. If the jadeite jade is treated, it can only act as an ordinary accessory or ordinary product, no longer a precious stone, because its texture is damaged and durability is greatly decreased. After it has been worn for a certain period of time, irregular tension micro-cracks will appear.
It is the reason why the price of all natural jadeite jade is far higher than treated ones, which is the difference between precious stone and ordinary accessory.
If you want to buy jade as investment or buy a real precious stone, remember to choose A type jadeite jade.
What are A type jadeite jade, B type, C type and so on?
A type jadeite jade: all natural jadeite, without any treatment. This type of jadeite jade can be bought as a real precious stone or investment.
B type jadeite jade: the natural jade is soaked in a mixed strong acid solution. Next, soak it in epoxy resin mixed with hardener. Then take it out and heat it to harden it. This kind of treatment can improve the color and transparency of the jade. But its texture is damaged and durability is greatly decreased.
Be aware that B type jadeite jade can also be called "natural color jadeite jade", because it is not dyed, its color is really natural. Ask the seller "is it soaked in acid solution?" as an additional question to confirm the jade you buy is an A type one.
C type jadeite jade: colored or dyed jade.
B+C type jadeite jade: the jade is dyed after acid-treated and resin-filled, which results in beautiful color and great transparency. But the color is not natural and the durability is greatly decreased.
D type jadeite jade: this kind is not real jadeite jade. It is another kind of jade or stone but looks like jadeite jade. It pretends to be jadeite jade because jadeite jade is the most precious and expensive one in the jade-like minerals.
Identification of A type, B type, C type, and B+C type jadeite jade
Some experienced craftsmen and traders can examine jadeite jade with naked eyes, by its color and luster. To consumers, the best way to judge a piece of jadeite jade is to ask for an identification certificate by a testing centre. In Chinese testing labs, A type jade will be marked as A-Jade in the identification result. Click to See Our Sample Certificate
As we know, Chinese people consume a lot of jadeite jade. Jadeite jade is the most popular gemstone in China. Correspondingly, high-tech instruments and methods are invented to test jade types in mainland China, HongKong, and Taiwan. For example, they will use magnifying lens, ultraviolet fluorescence analysis, microscope, infrared spectroscope, visible light spectroscope, ultraviolet lamp, so on and so forth. And judge from optic character, refractive index, absorption spectrum, and so on.
Jadeite
JADE (jadeite), Na (Al,Fe)Si2O6.
A. Jadeite nodule, top (height - 8.5 cm) from Guerrero Negro, Baja California Norte, Mexico. Cal Graeber Minerals. (© photo by Jeffrey A. Scovil)
B. Jadeite (height - 6.9 cm). Norman Steele collection. (© photo by Jeffrey A. Scovil)
C &D. Jadeite. Three-color snuff bottle (height - 7 cm), dated circa 1780-1850. (© photo courtesy of S. Bernstein & Co. San Francisco, http://www.bernsteinjadeart.com/ ) The carving on this snuff bottle is described as follows: "two sages cormorant fishing among lily pads during the springtime. The artist has used the natural coloration of the original jadeite boulder masterfully. The colors depicted are emerald green, white and gray-black. The relief work is well rendered with a high degree of polish which is the result of the application of chamois or deer skin repeatedly on to the surface." (© photo courtesy of S. Bernstein & Co. San Francisco, http://www.bernsteinjadeart.com/) E. Jadeite (width - 2.8 cm). Norman Steele collection. (© photo by Jeffrey A. Scovil)
DESCRIPTION: Pyroxene jade consists wholly or largely of microcrystalline, typically blocklike grains of jadeite. The size and arrangement of the grains appears to account for the unusual toughness of this jade and also its relatively common grainy or dimpled appearance, which is evident when fractured surfaces are viewed with a handlens or simple microscope. Guatemalan jadeite, which is somewhat atypical, tends to be relatively coarse grained, commonly including grains large enough to be seen with the naked eye; in addition, some of it includes chromium-bearing minerals such as macroscopically discernible chromite. Some jadeitic jade -- e.g., that from the famous Myanmar (formerly Burma) localities -- contains noteworthy amounts of other minerals such as acmite, actinolite, albite, analcime, edenite, diopside, enstatite, kosmochlor, muscovite, natrolite, nepheline, prehnite, richterite, tremolite and wollastonite. Geologists, in particular, refer to these impure jades by special names -- e.g., those with noteworthy amounts of diopside and/or acmite, which are typically dark green or nearly black, are often termed chloromelanite. See THE JADES entry for colors and some of the other properties that pertain to both Nephrite and Jadeite jade. H. 6½ - 7 (typically slightly harder than nephrite) S.G. 3.28-3.40 Light transmission - subtransparent to opaque Luster - ranges from glassy to oily or porcelaneous Miscellany - many jade boulders have reddish, yellowish, orangy or brownish rinds.
OTHER NAMES: Scores of names have been applied to jadeite jade. Jill Walker in the tome edited by Keverne (1992) lists "common trade names" (i.e., both adjectives and complete designations for jadeite jade) as follows:
Apple - yellowish green jade. Black chicken - subtranslucent to opaque, unevenly dark gray to nearly black jadeite. Chicken bone - opaque jade ranging from white to tan or gray in color. Chloromelanite - subtranslucent to opaque, dark green to nearly black jade, typically containing noteworthy amounts of diopside and/or acmite; this designation is most frequently associated with jadeite jade from Meso America, but Fuquan (1979) also records "Jadeite (chloromelanite), an iron-bearing variety, is found in the province of Yunnan, Southwest China, and known as Yunnan jadeite.". Emerald - see Imperial. Fei-Tsui - name proposed by Ou Yang (2003-notes original reference) for "all precious stone jade composed of pyroxene group minerals." Galactic Gold - marketplace name given to a black jadeite that contains bright metallic inclusions (possibly pyrite). --This designation is given some of the jadeite jade from Guatemala (Ward, 1999). Hte long Sein (also called Tie, or Tian,long sheng) - a "fully saturated green" jade from the Pharkant mining district, northern Myanmar (formerly Burma). Kimpi - name sometimes given to reddish or brownish jadeite. Kingfisher (fei cui and some maw-sit-sit) - medium green jade. Imperial - subtransparent to translucent, medium green to bluish green jade. Moss-in-the-snow - translucent jade that is essentially white but has sporadic green streaks. Yunnan - translucent to opaque, dark green jade. USES: See the many things listed under the USES subheading in THE JADES entry. In addition, some jadeite has been faceted for use in, for example, rings. And, some translucent, virtually colorless jadeite has been fashioned into cabochons that closely resemble moonstone. Also noteworthy: Today, much Guatemalan jade is fashioned into replicas of Olmec and Mayan carvings most of which are sold to tourists. In addition, special attention is directed to the book by Ou Yang (2003); in chapters six and nine, she lists and illustrates a few uses and outlines processes of production and systematically considers jadeite appraisal and grading factors (color, transparency, brightness, grainsize, cracking, volume, and cut).
OCCURRENCES: Diverse -- e.g., in sequences of chiefly sedimentary rocks that have undergone relatively low-grade metamorphism and as dikes (lenses?) in serpentinites -- with less than a consensus among geologists so far as conclusions relating to their geneses; and as alluvial boulders derived from bedrock occurrences. Ou Yang (2003) lists the following occurrence designations: New Mine skinless stone ("unweathered ... in primary ... deposits"), Mountain stone (in mass wasting environments), Surface Water stone (angular pieces in rivulets), River stone (rounded stones in river beds), and Terrace stone (stones of whatever origin now occurring in terrace deposits). She also lists the following categories based on the common skins or crusts on these stones: Sandy skin (of various colors), water ("feels smooth") skin, and enamel skin.
NOTEWORTHY LOCALITIES: Tawmaw plateau -- e.g., from Hpakan district, near the Uru River, about 65 miles from Mogaung, northern Myanmar (formerly Burma); and near Manzanal, Motagua Valley, Guatemala. Shigley et al. (2000) tabulate localities and pertinent references for localities from which jadeite was recovered during the 1990s. One recently discovered (rediscovered?!!) jadeite deposit seems especially noteworthy: Translucent blue and blue-green jadeite, which closely resembles that apparently used for millenia, by pre-Columbian Mesoamerican Olmecs, was so-to-speak unearthed in 1998. -- A major hurricane-promoted flooding of the Motagua River of Guatemala, and consequent landslides moved large "bus-size boulders of Olmec blue jade" to, for example, river beds, where they were washed clean; in addition, the movements exposed jadeite veins here and there in the bedrock (Broad, 2002).
REMARKS: As already noted, some jade in the marketplace has been dyed, chemically bleached, coated with paraffin, wax or some resin and/or impregnated by a polymer (Fritsch et al., 1992). Other known treatments, used singly, together, or along with those just mentioned include vacuuming, the application of acid (commonly acetic acid) or a bleach to remove extraneous stains or other coatings, and heating to improve colors. Remarkably -- in my opinion, ridicuously -- some of the dyeing has involved differential application of the dyes purportedly to make the jade take a "more natural appearance." -- Wow!
In general, jadeite jade, unlike some nephrite jade, does not become dull with the passage of time.
It seems a bit ironic that the designation China jade is sometimes used in an almost generic way to refer to jadeite jade even though most jade pieces from China are nephrite jade.
A jadeite boulder, reported to be the largest ever found, is on display in front of the Myanmar Gems Enterprise headquarters at Yangon, Myanmar (Koivula, Kammerling and Fritsch, 1992, p. 132). Apparently recovered from the Khy-Siu mine in the Mogaung area of Myanmar (formerly Burma) in July of 1982, the boulder has a circumference of 8.75 meters (~29 feet) and has been calculated to weigh about 33 metric tons (36 tons).
SIMULANTS: See those given in THE JADES introductory entry. In addition, it seems noteworthy that some items fashioned from nephrite jade have been marketed as jadeite.
Jadeite-resin doublets etc. - Such assembled stones, along with acid-treated and both resin-filled and resin-impregnated jadeite are well described by Ou Yang (2003, Chapter eight).
***Synthetic jade - "General Electric (GE) Gem Technology has developed a proprietary process for manufacturing synthetic jadeite . . . The samples [supplied the GIA Gem Trade Laboratory] ranged in color and quality ... but the finest green material rivaled 'Imperial' jade . . . [this . synthesis is said to be] achieved in a high pressure environment . . . [and] The gemological properties of the small number of samples we have tested to date overlap those of natural jadeite." (Moses, in Moses et al., 2002).
REFERENCE: Hargett, 1990; Ou Yang, 2003.
A. Jadeite nodule, top (height - 8.5 cm) from Guerrero Negro, Baja California Norte, Mexico. Cal Graeber Minerals. (© photo by Jeffrey A. Scovil)
B. Jadeite (height - 6.9 cm). Norman Steele collection. (© photo by Jeffrey A. Scovil)
C &D. Jadeite. Three-color snuff bottle (height - 7 cm), dated circa 1780-1850. (© photo courtesy of S. Bernstein & Co. San Francisco, http://www.bernsteinjadeart.com/ ) The carving on this snuff bottle is described as follows: "two sages cormorant fishing among lily pads during the springtime. The artist has used the natural coloration of the original jadeite boulder masterfully. The colors depicted are emerald green, white and gray-black. The relief work is well rendered with a high degree of polish which is the result of the application of chamois or deer skin repeatedly on to the surface." (© photo courtesy of S. Bernstein & Co. San Francisco, http://www.bernsteinjadeart.com/) E. Jadeite (width - 2.8 cm). Norman Steele collection. (© photo by Jeffrey A. Scovil)
DESCRIPTION: Pyroxene jade consists wholly or largely of microcrystalline, typically blocklike grains of jadeite. The size and arrangement of the grains appears to account for the unusual toughness of this jade and also its relatively common grainy or dimpled appearance, which is evident when fractured surfaces are viewed with a handlens or simple microscope. Guatemalan jadeite, which is somewhat atypical, tends to be relatively coarse grained, commonly including grains large enough to be seen with the naked eye; in addition, some of it includes chromium-bearing minerals such as macroscopically discernible chromite. Some jadeitic jade -- e.g., that from the famous Myanmar (formerly Burma) localities -- contains noteworthy amounts of other minerals such as acmite, actinolite, albite, analcime, edenite, diopside, enstatite, kosmochlor, muscovite, natrolite, nepheline, prehnite, richterite, tremolite and wollastonite. Geologists, in particular, refer to these impure jades by special names -- e.g., those with noteworthy amounts of diopside and/or acmite, which are typically dark green or nearly black, are often termed chloromelanite. See THE JADES entry for colors and some of the other properties that pertain to both Nephrite and Jadeite jade. H. 6½ - 7 (typically slightly harder than nephrite) S.G. 3.28-3.40 Light transmission - subtransparent to opaque Luster - ranges from glassy to oily or porcelaneous Miscellany - many jade boulders have reddish, yellowish, orangy or brownish rinds.
OTHER NAMES: Scores of names have been applied to jadeite jade. Jill Walker in the tome edited by Keverne (1992) lists "common trade names" (i.e., both adjectives and complete designations for jadeite jade) as follows:
Apple - yellowish green jade. Black chicken - subtranslucent to opaque, unevenly dark gray to nearly black jadeite. Chicken bone - opaque jade ranging from white to tan or gray in color. Chloromelanite - subtranslucent to opaque, dark green to nearly black jade, typically containing noteworthy amounts of diopside and/or acmite; this designation is most frequently associated with jadeite jade from Meso America, but Fuquan (1979) also records "Jadeite (chloromelanite), an iron-bearing variety, is found in the province of Yunnan, Southwest China, and known as Yunnan jadeite.". Emerald - see Imperial. Fei-Tsui - name proposed by Ou Yang (2003-notes original reference) for "all precious stone jade composed of pyroxene group minerals." Galactic Gold - marketplace name given to a black jadeite that contains bright metallic inclusions (possibly pyrite). --This designation is given some of the jadeite jade from Guatemala (Ward, 1999). Hte long Sein (also called Tie, or Tian,long sheng) - a "fully saturated green" jade from the Pharkant mining district, northern Myanmar (formerly Burma). Kimpi - name sometimes given to reddish or brownish jadeite. Kingfisher (fei cui and some maw-sit-sit) - medium green jade. Imperial - subtransparent to translucent, medium green to bluish green jade. Moss-in-the-snow - translucent jade that is essentially white but has sporadic green streaks. Yunnan - translucent to opaque, dark green jade. USES: See the many things listed under the USES subheading in THE JADES entry. In addition, some jadeite has been faceted for use in, for example, rings. And, some translucent, virtually colorless jadeite has been fashioned into cabochons that closely resemble moonstone. Also noteworthy: Today, much Guatemalan jade is fashioned into replicas of Olmec and Mayan carvings most of which are sold to tourists. In addition, special attention is directed to the book by Ou Yang (2003); in chapters six and nine, she lists and illustrates a few uses and outlines processes of production and systematically considers jadeite appraisal and grading factors (color, transparency, brightness, grainsize, cracking, volume, and cut).
OCCURRENCES: Diverse -- e.g., in sequences of chiefly sedimentary rocks that have undergone relatively low-grade metamorphism and as dikes (lenses?) in serpentinites -- with less than a consensus among geologists so far as conclusions relating to their geneses; and as alluvial boulders derived from bedrock occurrences. Ou Yang (2003) lists the following occurrence designations: New Mine skinless stone ("unweathered ... in primary ... deposits"), Mountain stone (in mass wasting environments), Surface Water stone (angular pieces in rivulets), River stone (rounded stones in river beds), and Terrace stone (stones of whatever origin now occurring in terrace deposits). She also lists the following categories based on the common skins or crusts on these stones: Sandy skin (of various colors), water ("feels smooth") skin, and enamel skin.
NOTEWORTHY LOCALITIES: Tawmaw plateau -- e.g., from Hpakan district, near the Uru River, about 65 miles from Mogaung, northern Myanmar (formerly Burma); and near Manzanal, Motagua Valley, Guatemala. Shigley et al. (2000) tabulate localities and pertinent references for localities from which jadeite was recovered during the 1990s. One recently discovered (rediscovered?!!) jadeite deposit seems especially noteworthy: Translucent blue and blue-green jadeite, which closely resembles that apparently used for millenia, by pre-Columbian Mesoamerican Olmecs, was so-to-speak unearthed in 1998. -- A major hurricane-promoted flooding of the Motagua River of Guatemala, and consequent landslides moved large "bus-size boulders of Olmec blue jade" to, for example, river beds, where they were washed clean; in addition, the movements exposed jadeite veins here and there in the bedrock (Broad, 2002).
REMARKS: As already noted, some jade in the marketplace has been dyed, chemically bleached, coated with paraffin, wax or some resin and/or impregnated by a polymer (Fritsch et al., 1992). Other known treatments, used singly, together, or along with those just mentioned include vacuuming, the application of acid (commonly acetic acid) or a bleach to remove extraneous stains or other coatings, and heating to improve colors. Remarkably -- in my opinion, ridicuously -- some of the dyeing has involved differential application of the dyes purportedly to make the jade take a "more natural appearance." -- Wow!
In general, jadeite jade, unlike some nephrite jade, does not become dull with the passage of time.
It seems a bit ironic that the designation China jade is sometimes used in an almost generic way to refer to jadeite jade even though most jade pieces from China are nephrite jade.
A jadeite boulder, reported to be the largest ever found, is on display in front of the Myanmar Gems Enterprise headquarters at Yangon, Myanmar (Koivula, Kammerling and Fritsch, 1992, p. 132). Apparently recovered from the Khy-Siu mine in the Mogaung area of Myanmar (formerly Burma) in July of 1982, the boulder has a circumference of 8.75 meters (~29 feet) and has been calculated to weigh about 33 metric tons (36 tons).
SIMULANTS: See those given in THE JADES introductory entry. In addition, it seems noteworthy that some items fashioned from nephrite jade have been marketed as jadeite.
Jadeite-resin doublets etc. - Such assembled stones, along with acid-treated and both resin-filled and resin-impregnated jadeite are well described by Ou Yang (2003, Chapter eight).
***Synthetic jade - "General Electric (GE) Gem Technology has developed a proprietary process for manufacturing synthetic jadeite . . . The samples [supplied the GIA Gem Trade Laboratory] ranged in color and quality ... but the finest green material rivaled 'Imperial' jade . . . [this . synthesis is said to be] achieved in a high pressure environment . . . [and] The gemological properties of the small number of samples we have tested to date overlap those of natural jadeite." (Moses, in Moses et al., 2002).
REFERENCE: Hargett, 1990; Ou Yang, 2003.
Wednesday, May 6, 2009
Chinese jade art show
Jade carving-(bean-worm)
Jade carving-lizard
Jade carving-snail
Jade jewelry
Jade carving
Jade carving-Ruyi
Jade carving-fish
Jade carving
Jade Ruyi Jade
Jade
The myth of jade
Jade – a gemstone of unique symbolic energy, and unique in the myths that surround it. With its beauty and wide-ranging expressiveness, jade has held a special attraction for mankind for thousands of years. This gem, with its discreet yet rather greasy lustre, which comes in many fine nuances of green, but also in shades of white, grey, black, yellow, and orange and in delicate violet tones, has been known to Man for some 7000 years. In prehistoric times, however, it was esteemed rather more for its toughness, which made it an ideal material for weapons and tools. Yet as early as 3000 B.C. jade was known in China as 'yu', the 'royal gem'. 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. Today, too, this gem is regarded as a symbol of the good, the beautiful and the precious. It embodies the Confucian virtues of wisdom, justice, compassion, modesty and courage, yet it also symbolises the female-erotic. A visit to the jade market, be it in Hong Kong or Rangoon, or at one of the Hong Kong jade auctions organised by Christie's, can give some idea of the significance this gem has for the people of Asia.However, as long ago as the pre-Columbian period, the Mayas, Aztecs and Olmecs of Central America also honoured and esteemed jade more highly than gold. New Zealand's Maoris began carving weapons and cult instruments from native jade in early times, a tradition which has continued to the present day. In ancient Egypt, jade was admired as the stone of love, inner peace, harmony and balance. In other regions and cultures too, jade was regarded as a lucky or protective stone; yet it had nowhere near the significance that it had in Asia, which was presumably due to the fact that people knew relatively little about this fascinating gem. Fortunately however, in recent times, people's understanding of this gem, which fascinates not only the connoisseurs by its perfect interplay of hardness and toughness with an enchanting range of colours and fine lustre, has improved; and their esteem for it has been on the increase all over the world.
What is jade?
'Jade', or yu, as it is called in China, is strictly speaking a generic term for two different gems, nephrite and jadeite. The name is derived from the Spanish 'piedra de ijada', loin-stone, jade having been recognised by the Amerindians as a remedy for kidney ailments. Because of its beneficial effect on the kidneys, the stone was also known as 'lapis nephriticus'. That, indeed, is where the term 'nephrite' came from. Jadeite and nephrite are both regarded in China as 'zhen yu', 'genuine jade'. It was not until the beginning of the 19th century that mineralogists and gemmologists started to differentiate between them, since they bear a considerable resemblance to each other in terms of their appearance, their hardness and the properties they exhibit when being processed. Both are tough, since they consist of dense, close-grained, matted aggregates, but they differ from one another in their chemical composition and colours. Nephrite ranges mainly from mid to dark green or grey-green, but it can also be white, yellowish or reddish. Rarer, and somewhat tougher, jadeite displays hues which include green, but also white or pink, and reds, blacks, browns and violets. In both minerals, the way the colour is distributed varies a great deal. Only in the very finest jade is the colour evenly distributed. Both nephrite and jadeite often have veins, blemishes and streaks running through them, though these may not always be regarded as flaws. On the contrary, some of these patterns are considered particularly valuable.
Jade: from raw material to finished product
Jadeite is rarer than nephrite and is therefore regarded as more precious. Nephrite deposits have been found in China, New Zealand, Russia, Guatemala and the Swiss Alps. Dark green jade, so-called Canada jade, is also found in Western Canada. Jadeite is found in China, Russia and Guatemala, but the best stones come from Burma, now known as Myanmar. There, at the annual 'Gems, Jade and Pearls Emporium', blocks of jade in all sizes are auctioned. When purchasing the raw materials, the dealers need to be fairly lucky, since the nodules, blocks and fragments are sold either whole or after having been cut into slices, and there is only a very small window, the result of some initial grinding. So the buyer cannot see exactly what is hidden on the inside: valuable green jade, or an almost worthless, speckled or streaky material. It is not until the cutting process begins that the real quality is revealed. In the jade-cutting centres of Canton, Beijing and Hong Kong, the raw material is processed with carborundum and diamond powder. Since jade is, as a rule, not transparent, but has a fine lustre, the cabochon is the form best suited to it. Thin slivers, which can be worn as pendants, and jade bracelets are popular too. Round, cylindrical and flat shapes can be combined to make attractive necklaces. Traditionally, jade is processed into slender figures, filigree images or thin-walled vessels. This is sometimes erroneously referred to as jade carving. Unwanted material is in fact removed during the cutting process, and the stone is subsequently polished. Here once again we see the subtle difference between nephrite and jadeite: whilst polished nephrite has a surface with a resinous lustre, the glassy lustre of jadeite after polishing seems to shine almost like that of a mirror.
What distinguishes good jade?
For collectors as well as jewellery lovers, jade is a fascinating gemstone. In Asia, above all, it is collected as an antique. Besides the quality of the gem and its processing, religion and faith also play an important role. In the West, many people prefer to collect jade in the form of snuff-boxes, cigarette holders, small bowls or rings. Since each collector has his or her own taste and his or her own likings with regard to colour, style and shape, it is no easy matter giving definite advice on the purchase of jade objects. However, jade is, at the same time, a wonderful gem, not only in its traditional guise, but also in more modern designs. Especially in recent years, creative jewellery and gemstone producers have come up with some wonderful, up-to-date jewellery design, thus sprucing up the image of jade, which had had rather a traditional character for quite some time.In general, the value of jade is determined according to its colour and the intensity of that colour, the vivacity and texture, and its clarity and transparency. Likings for particular colours vary very considerably from region to region and culture to culture. In green jade alone, the connoisseurs differentiate between seven main qualities, from the intense, even green of imperial jade, via apple green and spinach green, all the way to the lighter and to more heavily speckled shades of green. These special nuances often overlap and can hardly be recognised by the untrained eye. In the USA and Europe, emerald green, spinach green and apple green are regarded as particularly valuable. In the Far East, on the other hand, pure white or a fine yellow with a delicate pink undertone is highly esteemed. In the world of jewellery, the fine violet nuances of lavender jade are very popular. It is however the rare, emerald green of imperial jade, which shines through at the edges, a colour of incredible depth, which fetches the highest prices. Unfortunately, since not only good and natural jade is offered for sale, but often fake or poor-quality products or stones which have been coloured or otherwise treated, it is advisable to buy good jade only from reputable dealers and jewellers, whether the purchase is being made for a collection or as an individual piece of jewellery. Symbolic energy and beauty, the traditional and the modern are combined in jade in a particularly harmonious way. And in gemstone therapy it is said that jade 'stimulates creativity and mental agility on the one hand, while also having a balancing and harmonising effect.' So this beautiful gemstone brings us joy, vivacity and happiness all at the same time – and what, in our times, could we possibly need more?
INTERNATIONAL COLOR GEMSTONE ASSOCIATION reserved the text copyright http://www.gemstone.org/gem-by-gem/english/jade.html
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