The Two Jades - Nephrite and Jadeite
One of the most historically remarkable gemstones ever, jade has maintained unparalleled significance in Chinese culture for thousands of years, with jadeite having particularly tremendous success in the Chinese market for over a century.
Jade has been revered internationally for millenia, known famously for it’s impact on the cultures of not just the Chinese, but also the Mayan people, the New Zealand Maori, and more.
Nephrite Jade and Jadeite Jade are two of the toughest gemstones in the world, they come in a variety of colors, and are closely intertwined with history across the globe.
Nephrite is the jade of ancient China, it comes in multiple colors but is typically seen in dark, earthy green tones, it’s more abundant than jadeite and tends to be affordable in jewelry except for in very high qualities.
Jadeite jade was relatively unknown in China until it was pursued by an obsessed Chinese Emperor in the 1700s and by the 1900s it was a hit.
It’s rare, can come in vivid translucent green colors fetching millions of dollars, and has historical and cultural significance in the Western hemisphere spanning thousands of years.
Jadeite Quality Factors
At this time, the 2nd highest per carat jewelry item ever sold was actually jadeite jade. It’s known for its rarity and value, so many customers don’t fully grasp the array of prices it can come in.
Jadeite absolutely can be affordable, but the more rare the piece – the more expensive.
Jadeite quality is judged by a combination of color, translucence and texture.
Jadeite’s most valuable quality is called “Imperial” and is characterized by it’s exceptional fine green color, it’s high translucence and it’s even texture.
Green is the most coveted color of jadeite and therefore the most valuable, followed by lavender and then ice.
Translucency in jadeite can range from opaque to highly translucent, with highly translucent specimens not only being more rare and more desirable, but tougher as well.
Texture refers to the consistency of color in the gem.
A combination of fine color, translucency and texture results in the finest quality of jade.
How to Find Natural Jade
Treated jade, known as B Jade, C Jade, or B + C Jade, is brittle, has unstable color, and it isn’t rare – it’s usually just a scam because unscrupulous sellers often sell it as “natural.”
Treated jade is only worth about 5 - 10% the value of the natural jade.
How to make sure that the jade you’re buying is natural and guaranteed untreated?
Make sure that the seller is offering a gem report from a reputable lab like GIA or AGL.
Here are a few more fun facts to know when shopping for jade:
1) Jade is not priced per carat.
2) Natural jadeite was probably cut or carved in China but so was ‘B Jade,’ so just because it comes from China – that doesn’t mean it’s natural.
3) Unconvincing ‘B Jade’ often has vivid colors, even rich pinks and blues. Natural jadeite tones tend to be soft and earthy. So yes, jade can be multiple colors and still
be natural, but if it looks like candy it’s definitely not.
Jade as a mineral
Jadeite is a peroxy mineral. It is monoclinic. It has a moss hardness of about 6.5 to 7.0 depending on the composition. The mineral is dense with a specific gravity of about 3.4.
Nephrite tends to have a resinous luster while jadeite is more vitreous.
Nephrite is by far the more common form of jade. nephrite ranges in color from mid to dark green or gray green but it can also be white yellowish or reddish.
Why wear Jade?
Jadeite bangle bracelets are said to protect the wearer and absorb negative energy. Jade bracelet is very durable so it will not break or chip easily.
According to Feng Shui, jadeite can influence not only health but prosperity.
It is considered a dream stones by ancient cultures. Jade is used today to dream solve, access the spiritual realm and encourage creativity.
The finest quality jadeite is almost transparent with a vibrant emerald green color. It is known as Imperial Jade. The royal court of China once had a standing order for all available material of this kind and it's one of the world's most expensive gems. Lavender is the next most valuable color it is rated good for everyday wear avoid direct sunlight and exposure to heat which may cause color to fade.
Jade was prized for its hardness, durability, musical qualities and beauty. In particular, its subtle translucent colors and protective qualities caused it to become associated with Chinese conceptions of the soul and immortality.
Gold was considered to be a symbol of heaven. The importance of jade stone in Chinese culture as reflected in its status as a symbol of goodness, preciousness and beauty to the Chinese jade stone is also the embodiment of the Confucian virtues of courage, wisdom, modesty, justice and compassion.
Many Chinese wore Jade pendants and ornaments to indicate social status. Ancient beliefs associated with the power of jade still exist including the practice of wearing jade bracelets for protection.
Chinese parents often give their daughters or sons Jade bracelets to remind them of the parents protection and love. Jade is believed to bring luck just like a four-leaf clover is considered a symbol of good fortune. Jade is thought to have protective lucky charm energy.
How to take care of Jade
Untreated Jade likely won't crack however it's possible that treated Jade will because the treatments damage and weaken the surface. It may be dark or light blue in color and is slightly opaque. You'll likely notice color variations in the stone as well chlorine which is often added to water in pool and tap water, can be harmful to Jade so make sure you take off your Jade jewelry before you swim or take a shower.
Jade is more durable than glass if you wear a piece and it breaks very easily it definitely is not Jade. Even the soft nephrite Jade should not break easily if the piece is made from jade then the inside should be composed by tiny mineral particles. You can see the term type of jade is often thought to be a grading term indicating the highest grade of jade. In fact the grades of a B and C refer only to jadeite treatments and do not address any other quality parameters such as color, clarity or luster. The Stone Age Indians in Central America made jadeite articles but it is said that carving even simple objects took a long time.
Jadeite was found in Europe but perhaps very little was imported into China. Now the majority of the world's jadeite comes from Burma.
History of Jade
There are two kinds of materials that are called jade.
There's nephrite, which is amphibole.
And jadeite jade, that term is used because jadeite is a mineral name, not really a substance name.
The significance of jade owes to its utility that has been known by our ancestors.
Since the essentially late stage Neolithic.
So both types of jade were recognized as being tough materials.
And first were used as tools, mainly axes and powders, and eventually because some of them were beautiful, they got transformed into cultural objects, and objects of high value.
Both jades are types of rocks but they're essentially made up a single mineral, and have been used for a long time.
How is Jade formed?
Nephrite is tremolite-actinolite rock.
And jadeite, or it might be more generally called pyroxene jades, are composed of
a jadeite, the mineral sodium aluminum silicate, and there are also now some more calcium rich versions, like omphacite jade.
Which has mixtures of jadeite and dioxde in solid solution.
So one of the critical things in terms of understanding where jadeite forms is its density.
Jadeite is a dense mineral.
If we compare minerals that are made of the same elements.
Sodium, aluminum, silicon, and oxygen.
Most have a low density. So quartz is 2.66 grams per cubic centimeter, Albite a little bit lower. Nepheline about the same, and analcime even lighter.
But jadeite is almost 30% more dense than these other minerals. It means it must form at high pressure, compared to these other minerals. So in terms of the jadeite paragenesis, or the conditions under which jadeite or jadatite, which is the rock name forms on Earth. We know it's first is composed essentially of jadeite.
It is found typically as veins, and blocks, and what I call suppan serpentinite mélange. Serpentinite is the product of hydration of the Earth's mantle, which then when raises to the surface, we recognize it as the green serpentinite. Some of it is actually gem quality.
And the other aspect is that, jadeite or jadeite jade is associated with terrains, areas on Earth, that have recorded high pressure relative to low temperature. So the places where this is found are called blueschist belts. They're former coalitional areas. Eclogites, and amphibole eclogites or other places where you find jadeite sort of along with them. And these are mostly found in the scars of continental block collisions.
Where is Jadeite found?
An important factor in terms of sourcing jade is they're almost always
associated with lateral falls on the planet, much like the San Andreas in California, or the Sagaing Fault in Myanmar.
So if we actually look at a map, where the blueschist terrains, you can see that they form linear bands. And they represent the former convergence of the tectonic plates on Earth. And then the square blocks with green filling, are places where jade, jadeite jade had been found up until about the year 2000. And you can see they're generally associated with these areas of blue triangles.
However if we jump to the present, there are many more jadeite occurrences that have been found.
Now we're really dealing with 16 different deposits known worldwide. I wouldn't say that's the end of it. But that's what we know now.
There are three most important ones and in fact, two of them are related.
There's the jadeite Tract or the Jade Tract, in northern Myanmar, formerly known as Burma. And then the Nansibon in the Sagaing division of Myanmar, which is about 70 kilometers away but it's in a different state. And it is distinctly separated.
So the rest of them have had material found which in some cases has been able to be used as cultural jades in the past. Or it had been tried to be used to make gemological jades in the present.
But most of them suffer from a problem of either, they're in places that
are hard to get to, or they're in places where the government doesn't allow you to do that.
For example, in Japan the Omi-Kotakigawa area is basically preserved
by the government against exploitation.
And some places like the Ketchpel in the Polar Urals only has a field
season of about a month and it's extremely difficult to get to.
Many of the places are difficult to get to.
So the reality is the only two places where trade is extracted, really
is in Burma and in Guatemala (Motagua River Valley).
The Geology in depth
Jade is produced at convergence areas. And convergence is where the oceanic seafloor dives beneath another plate, and in that process the sea floor is hydrated, or has been altered by water.
And when that dives down, that water it gets released. So what happens is the sea water goes and rises up to part of the Earth's mantle, which has ultramafic rocks that turn into serpentinite.
And when you actually look at Jade samples, what you typically find is it is full of aqueous fluid inclusions, which is an indicator that it is probably formed from a fluid. So this is one of our earliest interpretations.
If you actually backtrack in terms of what we understand about subduction and convergent margins, we have determined based on facies assemblages that the places where you can see these green ovals are the kinds of places with the conditions that are right to form jadeite.
Mainly in the upper blueschist region, but sometimes deeper into the eclogite region. So this is where the jadine has been formed, and is presumably being formed. So we have another problem, which is getting it back to the surface. And that really requires the tectonics of our planet, which is one of the great features that we have that produces our mineralogical diversity.
The serpentinite areas in Guatemala have two different sources of jade. Notice they follow a fault, which is transform fault, which opened up in part of the Caribbean.
And then if you follow the upper transform fault, in other words one side is moving, the sides moving to the left and the other side is moving to the right.
And then there's another source of jade over here in the Rio San Juan complex of the Dominican Republic. They're all right along these faults, and the faults seem to provide a leak.
Leakage path whereby this serpentinite, which are low density compared to the rest of the stone around them, they tend to diapir, they rise to the surface.
So how do we actually observe jadeite occurrences.
In 1998 at the Tawmaw dike in the Myanmar Jade Tract, there looks like an intrusion, or essentially a big fat vein of the giant rock.
This and the other thing surrounding it seem to have tell you something either about what was happening along the fault, in which it was probably allowed to intrude. There is also albitite rock, which is very commonly found with jadeite rock. And below it is a different kind of alkaline amphibolite rock, which is pretty much only found in Myanmar.
The peridotite, which is the mantle, Earth's mantle, which is above the
subducting plate, will fracture because it's being tectonically deformed. And so it's brittle and tends to break.
The fluids from below will tend to go into that fracture, because the fracture will
actually open up slightly. The water will be absorbed and turned into serpentinite and in the vein gets left behind jadeite. If this process continues, which appears to do, because we can see evidence in the case of multiple fracturing, and multiple generations of jade in any one source.
Because it's brittle it wants to fracture before now the softer serpentinite at right around it. This process continues thousands of times.
We believe it's associated with actual fracturing, which would mean earthquakes. So maybe earthquakes at depths are actually producing jade.
A sample Jade in Myanmar has the center as Jade with lavender in color, which is not the most common. Around the jade is material that was once serpentine or maybe ultramafic rock, which is reacted with the same fluids that produce the jade. But turned it into an amphibolite and the serpentinite which would be outside is lost. Because it's fragile compared to this rock. So the Boulder preserves the early formation of the veins. So that's what's known as primary jadeite. The jadeite is formed from the fluid directly in a fracture.
There are other sources of Jade, where it looks like that jadeite fluid has actually replaced another rock, rather than crystalise directly. And here is a model for that,
where it'd be a tectonic block. Probably of something not unsimilar to the composition of jade itself. And it gets fractured, and the fractures get replaced. And in fact, the whole rock may to be totally replaced by jade. And that's been we call that the replacement type of jade, or art type of jade.
Most deposits have a bit of both, some are demonstrably the primary type like in Myanmar and Guatemala. And other places like for example, in the Alps tend to have a lot of the replacement type.
Mining for Jade in Myanmar
So let's go on to these places where you can find jade, looking at a geologic
map but keyed in to tectonic structures and major bodies.
The northern part of Myanmar - the transform fault. It's the Sagaing fault. It's a major fault in Myanmar. Much like the San Andreas is in California.
The places where you find rocks that are of high pressure and the places where
jade has been found are highly correlated with one another.
At the town of Nansibon, which is essentially just a jade town. The only business there is for harvesting jade. Workers are all in white overalls and covers, they have no pockets. They're not allowed to put anything in their pocket. And they're basically raking through the debris of serpentinite and are looking for a little pieces of jade. And then they stick them in this milk can.
This is underground in a primary deposit where the white looking material is jadeite, and the grayish or blackish material is either serpentinite or altered serpentinite. There is amphibolite rocks around. But one of the things to look at is that the serpentinites are often enriched in chromium. And chromium is the element that gives imperial jade or feng shui its color.
And you can see that there's an emerald green corona around this inclusion
here, which tells you something about the reactions that are going on that
provide the elements that give some of its color.
So on that same trip, we were able to look at some of the alluvial jade mines.
So these are where the sediments around the edge of the serpentinite block have
been dug up to try and find the debris that weathered off them in the millions of years since it was brought to the surface.
And one of the things that people didn't know for a long time is how extensive the work that it's done there.
So there are literally millions of people living in northern Myanmar, whose only goal in life is to find jade, or supply the people who mined jade, or other aspects of
that kind of business.
Large trucks are being used to excavating areas, which people think has some of the jade in it. And if you look at this from Google Earth, you'll find that it's an amazing amount of excavations up there.
Mining for Jade in Guatemala
In Central Guatemala, Jade was found in more than 200 kilometers of distance. So it's really distributed, because it's along a fault. And then we found that there's another area totally different, totally distinct down in the southern area. And these are actually two distinct jade deposits. But the point is they're related.
The field of jade distribution is filled with cactus. The jade appears to have a little potassium in it and lends itself to grazing. So the cows would clean it off for us.
The biggest block we ever found, which has since been harvested. And it was attempted to be taken to Taiwan, but it didn't get there.
Another block in 2004, where they excavated around it. It was the source of an unusual kind of jade called jade lila or jade arcoiris, which would be–that's a colorful, very colorful kind of jade.
Mining for Jade in the Urals in Russia
Now moving on to the next area that would be a very important source of jade is the Northern Polar Urals in Russia.
So up here you can see this is the old boundary of some kind of collision. There the purple are serpentinite, which is what normally hosts the jade. And here are where jade has been found. Some of the material here is very nice. But again the working season is less than a month, and there's no way to get there. So that's part of the problem.
Another area, two areas, are the Yenisey River area in the Borus mountains
of Khakassia in Russia. Here again the high pressure rocks. And here is where the jade has been found so far. But obviously more possibilities there.
Here in Kazakhstan, in Itmurundy, there some of the high pressure rocks again with the stars. And here is the source of the jade, and you can see a lot of fracturing going on here.
So there is potential to find these areas. The problem is they're not easy to get to. There's not much in the way of roads and stuff in the area.
Mining for Jade in other parts of the world
So here is a complete map of the world. Basically color coded by geological terrains of different ages. Most of the things that we find are relatively young in this blue belt and the circle Pacific belt. The oldest material is up here in the Polar Urals.
There's another area in Japan, but as I said before the Japanese material is highly restricted to be utilized. And then our area in northern Myanmar.
There are a few other areas here.
Here's one of the Cyclades of Greece, which I've actually visited, and appears to have been very important in the late Neolithic and the early Classical periods for cultural jades.
So the summary is jadeite is formed where plates collide. Although it is rarely preserved, and part of that has to do both with weathering. The material disappears.
And the other is that you have to have the material brought from depth, perhaps as
deep as 70 kilometers, up to the surface.
Jadeite crystallizes from water. That's something that most people didn't expect. But it appears to be consistent with experimental work that has been done.
And the final thing is that whereas jadeite had been very rare, except for only being known in these two places, we have found many more places in the last 20 years. So I would say the prospects of finding more is very good.
Identification and the treatment in jadeite.
Traditionally the term jade refers to two type of mineral aggregates. That's jadeite jade and nephrite jade.
But besides these two minerals some other types of materials could also be sold as
jade in the market. So to identify these jade simulans will have to not only look
into their physical properties, or the appearance, but also have to rely on some more advanced testing methods.
Both jadeite and nephrite are silicates, but they're completely different minerals.
Jadeite is not exactly a mineralogical term. It is an amphibolite of varying compensation in the tremolite to actinolite series. So that is rich in calcium, and the magnesium, and iron.
Tremolite, or actinolite they tend to grow into more elongated crystals. Only when they're crystals interweaved to a very compact, felted, interlocking structure. There will then be called nephrite jade.
Sometimes tremolite or actlinolite could also form a more coarse, fiber structure that create this chatoyancy effect. In those cases, they will be called a cat eye instead of a jade, because their structure is not really compact, or tough enough as the nephrite jade.
In nephrite the most sought after color would be white. While there are also green, yellow, black, and other colors that could overlap with the color range of jadeite jade.
Well jadeite is a pyroxene group mineral that is rich in sodium and aluminum. In comparison to nephrite, the physical properties of jadeite like it's refracted index, the specific gravity, and hardness all tend to be slightly higher.
These two textures can be easily separated based on their basic gemological testing. And even from the appearance with enough experience it's also possible to
tell some differences. For example, the green jadeite they're usually colored by iron. Their color can hardly rival these type of vivid green color in jadeite that are
induced by chromium. And also the transparency of nephrite to be lower than those of top quality, semi transparent jadeite.
As mentioned, jadeite is a pyroxene group mineral. Pyroxene is a very large mineral group, and besides jadeite some other gemstones like diopside, kunzite, or hiddenite also belonged to the pyroxene family.
Here we have the general chemical formula of pyroxene and legerete here, represents for the T side. And that is the tetrahedral site in the crystal structure that is usually occupied by silica.
The common structure of these pyroxene mineral is actually consisting
of these single chains of silica tetrahedral. As for the other cat eyes is in the crystal structure, that you really occupied the X side site or Y side, that it's octahedron sites. As you can see there are quite a number of different many different
elements for both X sides and Y sides.
So the various combinations of these elements actually correspond to 20
different mineral species. And what we will look into today would be the sodium and calcium rich pyroxene.
Well this ternary graph is showing the classification for some of the sodium
and calcium rich pyroxene. As you can see at this top left corner. It's an end member that's rich in sodium and aluminum. At the bottom end we have dioxides and augite that both rich in calcium.
The mineral called omphacite is actually a solid solution of the jadeite and the calcium pyroxene. Basically it contains more calcium than jadeite at its X sides.
And another appearance in mineral called the kosmochlor, although it's not showing this graph, it's also a solid solution with jadeite. And it contains more chromium than jadeite at its Y side.
Both omphacite and the kosmochlor floor could coexist with jadeite in the jade. Or they could also be the primary mineral of a rock. Their appearance can really resemble the jadeite jade.
The typical color of omphacite would be really dark green, sometimes even close to black. However it's really not uncommon to see some chrome colored on the sides, and their appearance can really reach those of top quality, fun quality jadeite.
The texture, or the structure, of omphacite could range from coarse granular structure to a very fine texture.
Generally speaking, if we compare them against jadeite, then omphacite tend to have a more granular structure, whereas the typical interlocking fiber structure of jadeite is just less common in omphacite. However in those fine quality jade, it's always hard to tell the difference.
And the refractive index of omphacite could be slightly higher than jadeite sometimes. Although most of the time that would be just the same at 1.66. And in the spectroscope omphacite could also show the 437 nanometer line that is diagnostic for the jadeite jade.
If it contains chromium it may also show the chrome's line. Basically omphacite can have the exact same spectrum as the jadeite jade.
Now you can probably see the limitation of traditional gemological testing. Apparently it doesn't help so much in separating omphacite from the jadeite. Even though omphacite has already been recognized as a distinct mineral for a very long time. It's really not into the most recent decade that we really start to differentiate them from the jadeite jade in the gem industrial trade.
Nowadays these two very similar minerals can be accurately separated based on some spectroscopic or chemical analysis. For example the Raman spectroscopy is one of the important technologies used in GIA labs for jade testing. Raman spectroscopy basically provides some detailed information of the molecular structure of a different material. It can help to identify different minerals species accurately and non destructively.
As we've mentioned jadeite and omphacite has quite similar chemical structure. You may also see some similarities in their Raman spectrum. But still by carefully comparing each peak position these two mineral can be accurately separated.
Sometimes jadeite and omphacite can occur in the same piece of jade. So actually the internals of jadeite and omphacite is quite common in nature. And a lot of the jade could contain a small amount of omphacite. And they could also be colored by omphacite to some degree.
Like in this pendant, the white area is jadeite, and the deep green there
is identified as omphacite. So they can also coexist with many other types of minerals.
If a rock contains too much additional components other than jadeite, then it should not be considered as a jadeite jade anymore. For example albetite is a type of feldspar. It's a very common excess mineral in jadeite. When feldspar becomes the primary mineral of a rock, the property of that rock would be quite different from jadeite jade.
In those cases it will be just more appropriate to say that's a rock consisting of jadeite and feldspar. The bi-colored bangle here is another good example. The lighter colored area is jadeite while the deep green area is identified as a type of amphibolite. The amphibolite takes up nearly half of this piece so again this would be more of a rock.
Another intriguing example of a rock consisting of jadida and amphibolite. What's interesting about this piece is that this bit contains both jadeite face, and the
showing on the right image it's a lighter colored rejion. And they also have
amphibolite face that displaying its cat eye effect, created by parallel fibers.
Also worth to mention as that the amphibolite that are associated with jadeite
are not the nephrite but there are other types of amphibolite, mostly rich in sodium, such as the richterite. And it sometimes can be also manufactured into gemstones and really resemble the jadeite and nephrite. But they are not considered as a jade.
Another pyroxene-bearing rock is maw-sit-sit. The typical appearance of a maw-sit-sit is very deep green mottled with black spots and streaks. And their transparency tends to be quite low. A lot of time they are nearly opaque. The mineral composition of maw-sit-sit can be quite complicated and varies a lot.
Most of the time it contains a fair amount of kosmochlor along with other minerals like jadeite, sometimes naturalite, feldspar, or chromite. Their physical properties can also vary a lot, largely depending on its mineral composition.
Maw-sit-sit is not really considered as a jade in most parts of the world. And it is more like jadeite simulant. Apart from all the pyroxene-bearing rocks we've mentioned, a lot of the simulants of jade in the market now are completely different minerals.
For example, serpentine is the type of metamorphic rock that usually come in
yellowish-green or brown color. Actually, serpentine has been carved into artifacts long before jadeite became popular.
But as you can see, it's luster and density is not really comparable to the jades. Quartzite is also another common simulant of the jades. Natural quartzite usually comes in yellow, light yellow, white color, sometimes green, but it can also be dyed different colors to imitate the jadeite.
Also the aggregate of hydrogrossular garnet may also be sold as jade in the market, and they could really resemble jadeite. Sometimes they're sold under the name African jade.
Regarding the nomenclature of jade, there are always discussions
going on internationally. As for GIA, an update was made in the year 2012.
Since then, apart from the jadeite jade and nephrite jade, we have also included
the green omphacite as a type of jade when it shows similar properties and the appearance as the jadeite.
Fei Cui in Chinese
In Chinese, there is a term called fei cui that has been used for stones, the jades from Burma since around 18th century. The original meaning of this term is a type of kingfisher bird with both red and blue-green feathers.
This word is actually composing of two characters. The "fei" means red, and the "cui" means blue-green. So in a very long period of time, fei cui has been used primarily for jadeite jade until people start to realize that some of the so-called fei cui are actually consisting of other types of pyroxene minerals.
Nowadays the definition for fei cui has been broadened to also include the rocks consisting primarily of omphacite or kosmochlor. However, this term hasn't really been widely used outside China.
Treatments in Jadeite - what does A jade, B jade, C jade actually mean?
Using ABC to describe different types of treatments in jade has been especially
popular in jade trading or in Asian markets.
A jade refers to stones that are completely natural or has been waxed.
B jade means the stone has been bleached, and the polymer impregnates it.
C means that the stone has been dyed.
A stone being both bleached, impregnated, and dyed, known as the B plus C jade.
First, let's look at waxing, which is not really a treatment. It is more like a finishing process for jadeite, as well as many other types of translucent gemstones. A lot of jadeite will go through this waxing process after it's been polished or carved.
So all the wax can cover the surface peat and fractures and give the stone a more bright look. The presence of minor wax on the surface won't really affect the value of the stone, and that stone will still be considered as an A jade.
Impregnation is perhaps the more common treatment in jadeite. This treatment actually involves two steps. The first is bleaching, and then second step is impregnation. The stone will be immersed in hot acid. That acid will bleach out all the oxidation stain and the impurities in jadeite. And after that, the stone may become quite porous or brittle.
In the second step, those open fractures will be then filled with polymer. This stabilizes the stone and also improves the luster and transparency of the stone. In the before and after image, as the brownish oxidation stain has been removed, the green color also appears more vivid. Sometimes these polymer-filled fractures could be visible under magnification.
Because the polymer is softer than the jadeite, it tends to be grounded down over time and leave this kind of a groove or the so-called orange peel effect on the surface.
However, this feature is not always seen in B jade, especially in the newly
polished materials. So the UV fluorescence could sometimes provide evidence of the treatment.
Natural jadeite are usually inert under UV light, which means they don't
have any fluorescence, whereas a polymer may sometimes produce strong blue or yellow-orange–yellow-green fluorescence.
However, nowadays more and more B jade doesn't have any UV reaction so the absence of these UV fluorescence does not necessarily prove a stone is natural.
To identify the treatment, the impregnation in jadeite, most gemological labs will rely on the FTIR spectrum to detect the fillers.
If we compare the natural jadeite against the polymer-impregnated one, we are focusing on the 2800 to the 3000 wavenumber region. And this is where all the vibration bands of the organic fillers may occur. In natural jadeite this region will be clear, whereas any polymer or wax in the stone may induce some sharp peaks in this region. By looking at these FTIR features, we can tell whether a stone has been waxed or it has been polymer impregnated.
Jadeite could also be dyed to different colors, and that will be the C jade. And a lot of the time the dye is added to the polymer filler, and that will be the B plus C jade.
Nowadays B plus C jade is much more common than pure C jade.
So in some dyed material, you can see the dye concentrations along the grain boundaries under the magnification. The natural jadeite, the natural greens veins are usually associated with green jadeite crystals or some other minerals like we mentioned earlier.
In magnification they may appear more diffused. The UVB spectrum could also provide some evidence for chrome-dyed jadeite. The natural chrome-colored jadeite will show a spectrum that's quite similar to an EMR spectrum with broad band in the yellow-orange and blue-violet region. And there could also be chrome lines in the red to yellow region.
In chrome-dyed samples, their UVB spectrum will show strong dyed band in
the yellow to orange region, and there will be no chrome lines. All these features may also be easily observed with a handheld spectroscope.
Jadeite could also be partially dyed to mimic the mottled green color. Some of the so-called blue floating flowers or green floating flowers could also be dyed. GIA's lab has encountered this type of a sample that contains both dyed green patches and some natural green veins like shown this fluorescence image. All the green patches associated with strong fluorescence are dyed, whereas there is a small area circled here that's actually proven to be natural green color. And it doesn't show any fluorescence under the UV light.
Lavender jadeite could also be dyed. Some of the organic purple dye may show strong orange fluorescence under the UV light. And their UVB spectrum may also differ from those of natural manganese-colored lavender jadeite.
Sometimes the purple dye concentration along grain boundaries can be seen under magnification. However, some of the dyed lavender jadeite doesn't show these obvious features. Identifying some of the dyed lavender jadeite remains a challenge for gemologists.
Jadeite could also be coated to improve its surface luster. Sometimes color coating may be applied to improve its color. The coating materials are usually polymer, and they could peel off over time. So you can observe them under a magnification. Usually coating is quite easy to detect with routine spectroscopic testing like Raman or FTIR.
However, in some mounted jadeite jewelries, the coating may be
hidden by the metal. Like in this pendant, the green coating on the back is showing this strong fluorescence under the UV light.
However, you can see there is an area in the center that doesn't give any reaction. So that area, actually there's no coating there, which makes it quite difficult to detect filler, detect that coating from the opening from the back. Cases like this can be quite deceptive because the green coating at the back of the jadeite could affect the face-up color of the jadeite.
Jadeite may also be heat treated. Heat treatment can be applied to jadeite that contains some iron inclusion. By changing the iron valence state from 2 plus to 3 plus, it can develop some orange to red color. And heat treatment is very stable because it doesn't involve any foreign material or the change of the crystal structure. So this treatment is not really detectable.
Lastly, there are also assemblages like doublets of jadeite and other materials or triplets of jadeite layers joined by colored cement. Sometimes even carving could be assembled. Like this carving is an assemblage of hollowed out jadeite and some polymer. So from the magnified image you can see there is a very thin layer of green jadeite on top. And underneath it, that's colorless polymer. After mounting, especially in closed-back mounting, this kind of assemblage can be quite convincing.
The GIA identification report can provide some important information on the gemstone such as its species, whether it's natural or exotic, and the treatment. As for jadeite, all these treatments and the detectable treatments we've mentioned today could be shown on the report.
Also for the chrome-colored green jadeite, if it's proven to be a natural
stone without any treatment, the report may also state it as a-- known in the trade as A jade. Jadeite is such a special and sophisticated gemstone.
For some of you that may want to learn more about jadeite, here I would like to introduce this fascinating new collection in GIA's Richard Liddicoat gemological laboratory.
That is The Bishop Collection–Investigation and Studies in Jade by George Kunz. This work documents Heber Reginald Bishop's massive private collection of jades and includes research articles on every aspect of jade written by 28 specialists. It took over three years to produce this elephant volume. And there were only 100 sets made for a total cost of $100,000 US, which is equivalent to nearly $3 million today. These two leather-bound volumes contain numerous plates, whether color drawings, colored lithographs, copper engravings, and woodcuts. All is printed on
American handmade paper. Combined weight of both volumes is over 100 pounds. The digital version of this work will be shared with the public online through the internet archive.
The museum has some new exhibits that have recently been renovated. If anybody is used to the old hall, it's a little bit like going underground. It was actually
designed by Vince Manson, who used to be the director of dreams at GIA. And it's now totally open. It's a typical hall at the museum–a lot of vertical cases, more than 5,000 specimens. There's a gem hall, which is much like the old one, laid out by either gem variety or gem species. There's also a temporary gallery in there, which right now has a jewelry display called Beautiful Creatures, which is jewelry design after animals and also spanning jewelry of 150 years, which is the same age as the museum.
If you want to see that, which for jewelry aficionados would be a very exciting
thing to see otherwise. The hall is laid out based on mineral paragenesis, by the environments in which minerals form. There's a separate case on Mogok because of the important stones that come from there and quite other variety.
What gives jadeite all of its different colors?
White jade is essentially either pure jadeite or pure dioxide. But the color of white is due to light scattering on grain boundaries or fluid inclusions. There is a variety called water jade, which is essentially translucent to transparent with very little color. There the grain boundaries between the grains is smaller than the wavelength of light, so you don't get light scattering. Instead you get a sort of translucence.
The chromium color is-- so chromium substituting for aluminum, which is being kosmochlor substitution either in omphacite or jadeite, produces that emerald green color.
The lavender color is produced primarily in very pure jade that has manganese content greater than iron. What happens is if iron is in the Y site, it tends to quench the manganese coloring. So manganese has to be somewhat higher, and it's usually not very much, no more than a weight percent or so.
There is a blue variety of jadeite which is found in Guatemala and in Japan, and it is an intervalence charge transfer kind of color between iron and titanium, and often is found or observable in the offsite varieties than in pure jadeite itself. Those are really the colors due to replacements with other elements.
The other thing is jadeite can be colored by staining. And so often the highly variegated jades which are very popular for carving actually have influxes of either the iron oxides or iron titanium oxides that cause them to be the ochre colors.
In the cases in Myanmar where the boulder conglomerates are very, very thick, there is an infusion of a chlorite coloration into veins in the fractured jadeite blocks that produce a dark green or almost black color. Black jades are generally-- they're really very, very dark green. It's just that they're so saturated that they look black.
The value factors with jade
When we look into the quality of jadeite, basically there are a few factors we can look into versus the color. Definitely for all the colored stones, basically color would be the most important value factor.
So for example, in green jadeite, the top quality, chromium-rich jadeite, so-called the imperial green, will command the higher market price. Also, lavender jadeite could also be quite valuable.
Next would be transparency. Basically the higher the transparency is, the better quality it is. Usually when the grain in the jadeite structure-- when the jadeite is very fine, they tend to show a higher transparency.
One of the things that I've observed from colleagues who are better at gemology is that you'll take an emerald green cab, you put a light behind it, and if it has a lot of the black spots, which often mean there's little pieces of chromite in it, that lowers the value. Also a lot of feathery texture tends to lower the value. The more it looks like green glass, the higher the value.
Jade fluorescence and why that happens
For natural jadeite or omphacite, usually they don't fluoresce unless there is some additional mineral that may cause fluorescence. Then that's another story.
Most natural jade pieces won't fluoresce. And the fluorescent one we're showing in the presentation is treated with polymer. Some types of polymer may show strong fluorescence, and that actually can be a very handy tool to separate some of the impregnated jadeite.
And also some of the wax–some of the jadeite, if it's been waxed, especially for carvings, if the wax traps into those carvings, the grooves on the carvings, you might also see some blue fluorescence along those grooves.
If anybody has seen academic talks, jadeite is notorious for its cathodoluminescence. Under an electron beam you see all kinds of colors and textures that you otherwise can't see. And I actually have been to a talk by Sorena Sorensen where people applauded her slides which showed the colors of cathodoluminescence in jade.
Definitely there are like for cathodoluminescence, some of the jadeite may
show strong fluorescence. And we can see the growth pattern of the jadeite under the cathodoluminescence.
What about jade found in British Columbia? Is that actually nephrite?
I'm unaware of any jadeite, jade in BC. Certainly there's some important deposits of nephrite, and some of that nephrite has the imperial green color. And so it is chromium color. But I think that those deposits, again, are high up in the mountains. They're only available two months a year. And I understand that they're depleted.
And so now the material that's replaced it actually comes from Russia mostly. There's jade in California, of course, but it's never been utilized either archaically or in modern times for gem use.
And the other problem with it now is it's also associated with an asbestos deposit, BLM, the Bureau of Land Management, lands. And so even gaining access to it is very difficult.
Guatemala produces a lot of jade. Most of it is not high-quality gem jade. There's a black variety from Guatemala that's been sold, which is actually a rock of
terramite and omphacite. There is blue-green jade from Guatemala which is very rare, but is well known in the archaeological materials.
And there's another variety, the Olmec jade, which has little clouds, which are inclusion clusters usually of alamite inside a blue-green matrix jadeite. And we've only found a couple of pieces during our reconnaissance over the last 20 years.
So it's just too rare to be commercially produced. And there's sources in Cuba and Rio San Juan of Dominican Republic. They've been used, again, for artifacts. There were efforts to try and commercialize the material, but the qualities really aren't up to–Burma is really the definition of high-quality jade. And no other locality produces anywhere near either the volume or the quality to greatly compete.
What has typically happened is the material from Guatemala has been illegally
exported and then tried to be sold as Burmese jade. And those kinds of issues, as you can understand with things like rubies, when somebody says you have a Mogok ruby but it's actually from Africa, that poses a serious problem for people who want the imprimatur of a locality.
What are the physical characteristics of replacement jade?
The kind I was talking about geologically is–so there's primary jadeite, where it forms a vein, and there was nothing there before. It was a cavity that gets filled with the jadeite.
Replacement jade is usually an albite or a plagiogranite, which is an oceanic rock that the fluids that produce jadeite have permeated and partially replaced and produced new jadeite instead. Generally it's not the high-quality gem material, but it has been used a lot for artifacts, fashioning axes, and things of that sort. So it's more of what I would call the academic interest in archaeology and tone rather than the gemological.
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