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Identity HelpMineralogical studies

10th Jan 2010 21:01 UTCTrish Wilson

I note that the subject on pyrite has been closed, and that there appears to be a void here on the subject of archaic jade and the use of Raman Microscopy in the identification of minerals. Here are some links to the subject:


http://openlibrary.org/b/OL19931909M/Mineralogical_studies_of_archaic_jades


http://www.earth.sinica.edu.tw/webearth-library-en/journals/wpes/Vol2/No3/V2n3p239.pdf


http://www.ijvs.com/volume3/edition4/section1.html


Feature Article in the above link:



2. Non-destructive identification of minerals

by Raman microscopy

Ray Frost, Theo Kloprogge, and Jolene Schmidt

Centre for Instrumental and Developmental Chemistry,

Queensland University of Technology,

Brisbane, Queensland,

Australia



Introduction



The identification of minerals is, in many cases, based on techniques like X-ray diffraction, optical microscopy and electron microprobe analysis. A major disadvantage of these techniques is that the mineral crystals have to be destroyed either to a powder or a thin section. Raman spectroscopy has been used for the identification of minerals <1-5>. This paper describes the application of Raman microscopy <6> as a non-destructive technique for the identification of minerals, suitable also for single crystals as small as a few hundred micrometers <7>.

The identification of minerals generally starts in the field by visual examination by a geologist. Based on properties such as colour, crystal habitus, hardness, lustre, cleavage, etc. often in combination with detailed knowledge of the regional geological history a first identification of many rock-forming minerals is possible. It becomes more difficult for the more rare minerals mostly present in only minor amounts and often as small crystals. In many of these cases visual examination even by an experienced mineralogist does not give a definite answer and other analytical techniques are needed in order to come to an identification of a mineral. The classical petrologist or mineralogist will start with the preparation of thin sections of approximately 30 microns thickness of the rocks sampled in the field for examination under the optical microscope. Optical properties such as colour, pleochroism, refractive index, birefringes, etc. allows minerals to be identified. However, this method is rather timeconsuming and depends strongly on the experience of the geologist. Alternatively, minerals can be identified by their crystal structure by X-ray diffraction and chemical composition by methods like electron microprobe analysis. In general, X-ray diffraction uses powdered samples, whereas the electron microprobe uses thin sections similar to those for optical microscopy, but without coverglass and coated with carbon. This can pose a problem for the identification of very small or rare crystals. An interesting non-destructive alternative is a spectroscopic technique generally known as Raman microscopy. In this paper we report a number of spectra of various minerals, all with crystals not larger than a few millimetres. This will show the strength of the Raman microscopy technique as it will show that each spectrum is unique and can be used as a sort of fingerprint for the identification of the mineral when a large enough database of mineral spectra is available.


Raman microprobe spectroscopy



The Raman effect is a light scattering effect (see for example The Spectroscopists Bookshelf: http://www.ijvs.com/bookshelf.html). In order to obtain the Raman spectra of minerals, minerals were placed on a polished stainless steel surface on the stage of an Olympus BHSM microscope, equipped with 5x, 20x and 50x objective lenses. No sample preparation was needed. The microscope is part of a Renishaw 1000 Raman microscope system, which also includes a monochromator, a filter system and a charge coupled device (CCD). Raman spectra were excited by a Spectra-Physics model 127 HeNe laser (633 nm), recorded at a resolution of 2 cm-1 in sections of 1000 cm-1 for 633 nm excitation. Repeated acquisitions using the highest magnification, were accumulated to improve the signal to noise ratio in the spectra. For the 298 K spectra, data were collected at 20-second intervals for 10 minutes at maximum magnification. Spectra were calibrated using the 520.5 cm-1 line of a silicon wafer. It should also be noted that the filters in the Renishaw spectrometer start to eliminate the Rayleigh line at about 150 cm-1. This makes the determination of bands below 200 cm-1 difficult and without reliability.

Spectra obtained with the microprobe normally consist of Raman bands superimposed on a background, which is a combination of the fluorescence and the instrument function. In the case of the HeNe laser and the measurement of the hydroxyl stretching region, the background is predominantly due to fluorescence and consists of a sloping linear baseline that is easily corrected. For the HeNe laser and the determination of the low frequency region, the background is predominantly a combination of the instrument function that is dependent on the behaviour of the notch filters, the grating-detector responses, and the fluorescent background. This background is induced by elements placed in the optical path between the sample and the entrance slit of the spectrometer. The background, although a complex function, is easily measured using the incandescent white light from the microscope. The measured spectra are then ratioed to this instrumental background to give the spectra as illustrated in the figures in this paper. Such a method ensures the correct instrumental function is taken into account and that the true spectrum is measured. Different instrumental profiles are obtained for the operation of different lasers.

Normally with conventional dispersive Raman spectroscopy and to lesser extent, Fourier transform Raman spectroscopy data collection times can be excessively long, particularly for minerals. Often for poorly scattering minerals such as clays, several thousand FT Raman spectra must be coadded to obtain a spectrum of sufficient quality. In the case of Raman microprobe spectroscopy with multiplex detection, data collection times are very short and spectra are easily obtained within 1 to 10 minutes. Typically a collection time of 60 seconds, in which 10 spectra are co-added, is used with the maximum magnification. Power at the sample is in the 0.1 to 1 mW range. This use of such low power is a major advantage particularly over that used for FT Raman spectroscopy where typically the power used for minerals is 100 mW for a spot size of 200  m. For Raman microscopy, the laser spot size is 0.8 microns and the laser power is between 1 and 4mW. Such low power means that there will be no heating effects and consequential damage to the mineral. It was found that the best quality spectra were obtained by scraping fresh crystals from a lump of the raw material on the metal support. Crystals of the kaolinite are easily observed under the microscope.

One of the disadvantages of Raman microprobe analysis is the fluorescence of the clay minerals which is particularly pronounced when using the HeNe laser at 633 nm and other lasers of similar wavelengths. Each of the laser lines used to excite the Raman spectra of the kaolinite polymorphs caused fluorescence that subsided with time. Even so difficulty of measuring the low frequency region with the 633 nm excitation was experienced and the use of the diode laser operating at 780 nm did not alleviate the problem. Obtaining spectra at 77K, meant that the instrumental background shifted with temperature. This shift may be related to the change in the fluorescence of the sample at liquid nitrogen temperatures. Unique spectra from kaolinite polymorph crystals were more difficult to obtain from ground or powdered samples. If the crystals are smaller than the resolution of the microscope then spectra are obtained from an area that covers several crystals and an averaged spectrum is obtained.

An advantage of Raman spectroscopy is that bands in the 200 to 400 cm-1 region are easily measured. Dispersive Raman spectroscopy inherently has the clay spectrum superimposed on the intense Rayleigh line. The use of Raman microscopy employing CCD detectors is greatly advantageous because of signal to noise improvement. Detectors in both FT Raman spectrometers and conventional dispersive instruments are photon noise limited. With a CCD detector this is no longer true: typically the noise from a CCD detector is at least 100 times less than from a semiconductor detector. The disadvantage of using Raman spectroscopy operating at the diode laser frequency of 780 nm is the loss of scattering efficiency. Raman scattering decreases as the fourth power of the wavelength of the scattered radiation, so the intensity of the Raman scattering at 780 nm compared to say 532 nm is ~7 times less. For the 633 nm (HeNe) laser, this factor is 2. Nevertheless, the disadvantage of this loss of efficiency is greatly outweighed by the advantages of the CCD detector. Further the advantage of using lasers operating in the 633 or 780 nm range rests with the reduction of the laser induced fluorescence which is a problem when using green or blue excitation wavelengths.

10th Jan 2010 23:25 UTCTrish Wilson

Shown here is a small Neolithic nephrite jade carving from Liaoning Province in northern China. It stands 7 cms. tall.


When this jade first came to our collection, we had no idea what the mineral inclusion was. What we could see was that it was raised slightly above the surface of the carving.

10th Jan 2010 23:31 UTCTrish Wilson

In April 2008 we had the material checked through Raman spectroscopy and received a hand-written letter (see attachments) from Dr. Llew Rintoul, Postdoctoral Research Fellow at the Queensland University of Technology.

10th Jan 2010 23:53 UTCRob Woodside 🌟 Manager

Most interesting. How large are the Pyrites or sculpture? I have never seen large pyrite xls in Jade before, but pyrite is ubiquitous. Pyrite often forms cubes so the one on the front looks OK. However the angles of the one on the back look a bit odd, even allowing for the curvature of the sculpture. Have you tried looking at this under ultra violet light? I only suggest this as someone talked of a pyrite paste on the closed thread. Forgers have used fluorescent glues until some one tells them about it and it might not show up in a Raman. Pyrite is not fluorescent. Again the relief seems high.

11th Jan 2010 01:14 UTCAlex Homenuke 🌟 Expert

Have you had the artifact positively identified as Jade - either nephrite or jadeite?

11th Jan 2010 02:08 UTCTrish Wilson

Rob, the height of the carving is 7.0 cms. The square pyrite inclusion on the shoulder measures 5 mm. and the one on the top of the head measures 11 x 7 mm. By the way, pyrite has been identified in ancient jades.


Please do a search for 'pyrite' and you will find the crystal shapes of this mineral.


Re the pyrite being raised above the surface of the jade, we have a number of examples of archaic jades which display this feature. We believe that in some cases, particularly the very ancient examples, i.e. the Neolithic carving I've shown on this thread, this could be caused because of the erosion of the jade.


The idea that the examples of pyrite shown on the closed thread are pyrite paste, is quite ridiculous.

11th Jan 2010 02:16 UTCTrish Wilson

Alex, the answer to your question is in my picture of the graph (Mindat - Neolithic pyrite b). The highest peak is tremolite, the next highest is actinolite. The two together constitute nephrite jade. The small peak is pyrite.

11th Jan 2010 16:27 UTCAlex Homenuke 🌟 Expert

Trish,

The reason this thread interests me is that in a past life I managed a jade mine and studied nephrite for a couple of years. I had never found a sulphide, let alone pyrite as an inclusion. My studies did not include ancient jades, though I do have a couple of pieces. I decided to try an internet search and wound up on EBay (item 350297676507). I had some doubt that the intense metasomatism would allow a sulphide to crystallize within a nephrite deposit - the attached picture has convinced me!

11th Jan 2010 17:04 UTCJolyon Ralph Founder

Ok.


I'm at a loss as to what the question actually is here. This section is entitled "Identity Help", what is it you wish to have help with? I think you have all the answers already.

11th Jan 2010 18:08 UTCRock Currier Expert

The question also entered my mind as to if the figurine was really nephrite jade. The color seems wrong and considering how much softer pyrite is than nephrite one would expect that it would undercut rather than stand out above the surface of the rest of the carving though one can understand how it might alter to limonite in a very old and probably buried for a long time carving. Has something as simple as a hardness test been run on the bottom of the carving?

11th Jan 2010 18:35 UTCRob Woodside 🌟 Manager

Trish says:

"Alex, the answer to your question is in my picture of the graph (Mindat - Neolithic pyrite b). The highest peak is tremolite, the next highest is actinolite. The two together constitute nephrite jade. The small peak is pyrite.


Have a look at these these Raman spectra:


Pyrite http://rruff.info/pyrite/display=default/R050070


Tremolite http://rruff.info/tremolite/display=default/R060311


Nephrite http://rruff.info/nephrite/display=default/X050001


Jadeite http://rruff.info/jadeite/display=default/R070117


Your spectrum is correct as labeled. It is a pyrite spectrum with nothing to do with tremolite or actinolite and has nothing to do with nephrite jade.


It would be interesting to see how deep these pyrites go into your carving. Since pyrite has a density nearly twice the other purported minerals a density measurement which is completely non destructive should tell the tale.


Pyrite is fairly easy to synthesize, so a real possibility is that they are a surface phenomenon and were grown there.


I agree with Rock about whether this is Nephrite jade.

12th Jan 2010 00:33 UTCEzekiel Hughes

I too have been searching the net for examples of pyrite in jade and came up with the New Zealand sample...here are all the pictures of the piece:

New Zealand


Alex, I'm still not a believer but will keep an open mind. I have heard rumors of pyrite inclusions in jade from around our area and have found jade like junk with flakes of pyrite...i guess i should have it tested...but I doubt it is what it appears to be. Also, what exactly is "New Zealand Greenstone Pounamu Nephrite Maori Jade"


Actual ebay link:
Ebay New Zealand Jade Link


Also, how come there aren't specimens of pyrite crystals on natural nephrite stones buried in the earth? That is if the idea of them growing after the piece was buried is to be believed.


Also, in regards to secondary tremolite growth, wouldn't the proper P & T be required? I think there are plenty of questions to be answered.


When I read of associate pyrite in occuances of nephrite, it is in association along with a dozen other minerals and rocks...notice the location of the pyrite in the NZ piece...in the black...serpentinite often has pyrite right?


Ironically the color of the piece Trish is showing us here could be jade...it is a product of secondary weathering (oxidization in in the proper soil enviroment...aka vulcanization) either before carving or after or it isn't jade. Can't tell jade by color alone. However most "red jade" isn't jade.

12th Jan 2010 01:04 UTCTrish Wilson

Alex, thank you for looking into pyrite found in nephrite jade. There is reference to it being found it ancient Chinese nephrite in the Mineralogical Studies published in ACTA Geologica Taiwanica.


Rock, nephrite jade comes in a wide range of colours. The small horned figure has likely been carved from multi-coloured jade that comes from Liaoning Province.


Picture attached shows two nephrite boulders from Liaoning, each weighing approximately 16 kgs.

12th Jan 2010 01:36 UTCTrish Wilson

Rob, re your query on how deep the inclusions of pyrite in the small horned figure go, I do not have a light that penetrates the jade. However we have other ancient jades with inclusions. None of these have been tested to identify the material or inclusions. From long experience of handling ancient nephrite, the crystal structure is visible on the weathered surfaces. As far as the inclusions are concerned, I believe they are pyrite, though I do realise that they may by pyrrhotite. Not being a geologist my education is lacking in being able to quickly identify inclusions and some secondary minerals seen regularly in archaic jades.


I am hoping that someone here may see something from the pictures below to make a positive identification.


The first lot of pictures are of a mythical animal. We do believe the base material is nephrite. The inclusions run in a very distinctive band through the left side.

12th Jan 2010 01:47 UTCTrish Wilson

The bulk of the inclusions in one of these jars is along the edge of the lid of one of them. The pictures show both the outside and inside of the same area, showing that the inclusions penetrate the jade. As you can see, they are raised above the surface on both sides. For someone in the know, this may identify them.

12th Jan 2010 01:51 UTCTrish Wilson

Close-ups of the same area.

12th Jan 2010 01:58 UTCTrish Wilson

This pair of bears shows the same inclusions, but they are randomly scattered.

12th Jan 2010 02:05 UTCTrish Wilson

All for now. Thank you for your attention.

12th Jan 2010 03:21 UTCAlfredo Petrov Manager

Air-abrasive carved serpentine, leaving the harder pyrite standing out. ...?

12th Jan 2010 03:55 UTCEzekiel Hughes

That would explain it nicely wouldn't it?

12th Jan 2010 05:27 UTCTrish Wilson

Air-abrasive???? That's a new one on me.


Please look at the top of the picture showing the outside of the lid of the jar. The interwoven structure of nephrite crystals should be very obvious.


Show me an example in serpentine where you can see this.

12th Jan 2010 06:10 UTCCraig Mercer

I think Alfredo has hit the nail on the head here. Serpentine....of course, it all makes sense now. I was actually starting to think it may be a manmade compound with the pyrite added, then some kind of air/sand or water wearing, thus explaining the exposed pyrites.

12th Jan 2010 06:31 UTCEzekiel Hughes

The link to the paper cited in the first post has some problems. Authors bought thier jades for testing at a market without additional authenication. they plan a second try. Notice it is self referencing mostly if not entirely. Also note in thier conclusion that acid washing will produce the same result....in the end it says nothing. i could go to my back yard and find some "jade" that has the felted look to it...but I dump that serpentinite into "junkite creek" which is over flowing right now....wait till the spring or tomorrow for me to post pictures of "jade" that is serpentine with the same felted look as real jade.

12th Jan 2010 07:12 UTCTrish Wilson

Afredo, Zeke and Craig --


You have totally missed the point here. The question was about the identity of the inclusions, not of the base material. We know exactly what that is.


Zeke, I really do not think you are in a position to judge the work done in ACTA Geologica Taiwanica.


Professor Hsien Ho Tsien is a member of the Faculty, Paleontology, Department of Geology, National Taiwan University, and was the guest editor of ACTA Geologica Taiwanica, Mineralogical Studies of Archaic Jades, 1996. The book is dedicated to Professor Li-Pin Tan in recognition of his work in pioneering studies of tremolite jade. Professor Tan graduated with honors from the Department of Geology, National Taiwan University in 1953.

About ACTA Geologica Taiwanica: “The Symposium on the Mineralogical Studies of Archaic Jades was organized jointly by the National Taiwan University and the Taiwan Museum, and was held on the campus of the University on January 12 and 13, 1996. The purpose of the Symposium was to discuss recent developments in mineralogical and geological studies of archaic jades, to exchange ideas and to establish scholarly contacts in this specialized field of research.

“During the Symposium eleven papers were presented in Chinese and English. Seven have been selected for this volume after final revision by their authors. Thus this volume represents the Proceedings of the SMSAJ.”

About the Department of Geology, National Taiwan University: “Active research on various geologic topics is the tradition of this Department. Major funding agencies include National Science Council, Central Geological Survey, Bureau of Environment Protection, Bureau of National Park Administration, Commission of Atomic Energy, etc. Research results appear in both domestic and foreign professional journals. The Department also issues one volume of high standard research report "Acta Geologica Taiwanica" annually, and cosponsors the Chinese journal "Ti-Chih" with the Geological Society of China and the Central Geological Survey.


“The Department has long been the major institution supplying the Republic of China with well trained geologists. Its alumni are engaged in various phases of geological work both in Taiwan and abroad. Because of the economic prosperity of the Republic of China in recent years, the increasing demand for geologists is expected.”


Professor Tsien used both documented and undocumented jades in his research project.

12th Jan 2010 07:55 UTCEzekiel Hughes

Trish, nor do I think you are in a position to talk knowledgably about jade. by what measure? you have as many questions as I yet attest to your jade without real question to it's authenticity...why? If I found a piece of "jade" as yours on the creek...in the wild...I would question until I got a real answer...not make stuff up to account for the anomilies. pyrite does not pop to the surface....tremolite does not recrystallize in damp soil...i try to give you the benifit of the doubt...and i will eat my own socks if you prove....PROVE....what you say is true...but what you say is beyond the literature....where are the samples beyond your 'archaics'? where is the proof? i would love to see it...I am free of bias....show me. i hold nothing agianst the professor...and he covers his rear in the paper well....read it...really read it.

12th Jan 2010 08:38 UTCTrish Wilson

Zeke, I am not here to have jades authenticated -- certainly not by you. Just keep a clean pair of socks handy.


It is clear that you have nothing to add on the identification of the inclusions.

12th Jan 2010 08:59 UTCEzekiel Hughes

You can not seperate the identification of the inclusions from the host rock based on a photograph...the whole rock is up for debate...that's the way it works. You can not pick and choose your arguments, you must accept all valid arguments to your theory...that's all anyone wants to do...it's not personal at all with me. I wish everything everyone told me about jade were true...really....When I ask for an opinion on Mindat I better well get one....even if it's from a know nothing like me....because maybe i know nothing! But my reservations are more than valid and should be respected as such...thank you

12th Jan 2010 09:13 UTCTrish Wilson

Zeke, I am more than willing to accept valid arguments, however, I'm afraid I don't view yours as such. You make it very clear that you know nothing. I do know who your teacher is, and the chance of widening your knowledge on jade is doomed. All I can see from your posts is that you are trying to disrupt any real discussion on my question.

12th Jan 2010 09:40 UTCHarjo Neutkens Manager

Zeke's arguments are valid.

Your last posting was not very polite, this is not the way to discuss here on Mindat.

Bottom line is, Trish, if you can't handle an open debate about a piece then don't.

12th Jan 2010 09:54 UTCJolyon Ralph Founder

Yet again, I fail to understand the justification for this thread except, perhaps, some strange self-gratification of the original posters. The inclusions have been identified as Pyrite.


Can the original poster please explain to me why I should keep this thread open, what are we debating here?

12th Jan 2010 10:10 UTCJolyon Ralph Founder

I don't think it's unreasonable to suggest this is some kind of hard(ish) amphibole mineral with pyrite inclusions. It might even be nephrite, I'm not an expert at that.


But because of the excellent state of preservation of the pyrite and the heavily weathered surface of the "jade", the only logical conclusion I can see that explains this is that it is a recent carving that has been treated with acid. Natural weathering would have likely caused more deterioriation to the pyrite.


Jolyon

12th Jan 2010 10:29 UTCTrish Wilson

Joylon, I did not come to this site to make trouble. I was interested to get some answers on the inclusions shown in the earlier thread, which you closed and moved, making the assumption that the inclusions shown and the entire object within which they were, were fake. I showed similar inclusions in the hope that someone here had something more realistic to add, rather than the silly idea that the inclusions were chewing gum or some other attachment. Some thought it was pyrite and some still believe otherwise.


I can work things out for myself and can see that there is nothing more to glean from the members. So you may certainly close the thread.


Your forum is infiltrated by Anita Mui through her good friend and assistant, Ezekiel Hughes, who was not content with addressing my questions within the legitimacy of this site. Read through some of his postings on her forum:


JadeJunkee

Post subject: Iron pyrite in nephrite?

PostPosted: Sat Jan 09, 2010 11:31 am

User avatar


Joined: Wed Nov 25, 2009 6:23 am

Posts: 36

Please review this thread on mindat and either jump in on that board or give me some of what you know with links to etc...


http://www.mindat.org/mesg-11-167252.html


~Zeke


JadeJunkee

Post subject: Re: Iron pyrite in nephrite?

PostPosted: Mon Jan 11, 2010 10:32 pm

User avatar


Joined: Wed Nov 25, 2009 6:23 am

Posts: 36

I'm trying to post links to two examples of real jade with pyrite inclusions....but seem to be failing....


I've heard of the stuff before and personally have some "semi-nephrite" with small flakes of pyrite...but i have trouble calling it jade as it is of such terrible quality...i call it an ugly garden rock.



JadeJunkee

Post subject: Re: Iron pyrite in nephrite?

PostPosted: Tue Jan 12, 2010 3:04 am

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Joined: Wed Nov 25, 2009 6:23 am

Posts: 36

I've decided to dial it up a notch and am calling in some renowned experts ;-) Trish has started a new post on Mindat....don't reply yet...let her bury herself for awhile....the moment you reply the mods will close the post because they don't want it to turn into a fight. let me get some undisputable, unbiased opinions from "untouchable" authorities....that last link was provided by Trish...one self referencing paper does not make a valid theory :-) I have no doubt myself...why do all her pieces have the exact same "weathering" patterns? why does the pyrite pop out? There is one close up she provided that gives me pause, but then reason takes over. where are all the rough jades with pyrite for sale? where are the examples not from her collection? .....why do i have to pay $50 to post on thier site if they really have all these archaic jades, shouldn't that be modivation enough to have an open site? Anita, your tenacity is impressive.


JadeJunkee

Post subject: Re: Iron pyrite in nephrite?

PostPosted: Tue Jan 12, 2010 3:44 am

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Joined: Wed Nov 25, 2009 6:23 am

Posts: 36

I sent the email out to someone i trust...might be a few days....don't get on the new thread...It'll only close it down.

12th Jan 2010 10:36 UTCBen Peters

Hi Joylon,


I suppose Trish's initial question is simply a call for opinions on the nature of the inclusions - to which some have been stated. Any piece of rock with photos posted might be some kind of fake, so I see no reason to be prejudiced against a sample which happens to be presented as archaic jade.


I am also interested to know if anyone with nephrite jade experience knows of any potential mining or river sources for material like this within China, assuming it is nephrite with pyrite inclusions?


Anyway, please leave the thread open; I am in possession of some similar material, and I am having some Raman tests done tomorrow. I will post the results tomorrow/Thursday. This should at least confirm some premises.


Thanks,

Ben

12th Jan 2010 10:42 UTCJolyon Ralph Founder

I'll leave the thead open for now.


>I am also interested to know if anyone with nephrite jade experience knows of any potential mining or river sources

>for material like this within China, assuming it is nephrite with pyrite inclusions?


Thank you, this is a far more reasonable question, and I'd hope someone would be able to help.


Jolyon

12th Jan 2010 10:43 UTCCraig Mercer

Lol......convenient 8-)

12th Jan 2010 10:44 UTCTrish Wilson

Great news, Ben. I for one look forward to your posting.


From our experience with Raman testing, the test for the mineral Nephrite is quick and simple. However, you may find they have more problems with the pyrite, if that is what it is.

12th Jan 2010 13:18 UTCBoris Erjavc

My guess is serpentinite. Specimens are all weathered, no matter natural or not, but all edges looks sharp what is result of grinding, rubbing or polishing. Weathering is always stronger on the edges, so the edges should be more damaged. I would agree with air abrasive serpentinite and than polishing.


Good luck


Boris

12th Jan 2010 20:21 UTCRob Woodside 🌟 Manager

Trish, no one here has doubted Pyrite and you have a Raman Spectrum to prove it. Why do you question the pyrite? You suggested Pyrrhotite as a possiblity. On a clean surface which the pyrites have (after many years of burial?), pyrrhotite would be more brown and weather more quickly than pyrite. Pyrite is non magnetic and rarely pyrrhotite (Troilite) is non magnetic, so seeing if a magnetised needle suspended on a thread is attracted would prove pyrrhotite which I very much doubt. Heating Pyrrhotite and sulfur produces pyrite. However the hardness difference between serpentine and pyrite would allow air abrasion to produce the relief we see and serpentine is a better host for pyrite as others have pointed out.

12th Jan 2010 22:43 UTCTrish Wilson

Rob, the paper I provided with the Raman spectra for pyrite was only for the small Neolithic horned figure. Of course you are correct in stating that the spectra was only for pyrite and not for nephrite. The enquiry I made was for the inclusions seen on the mythical animal, the jars and the winged bears. The shape of the crystals on these are different to those seen in the small figure. I should make a note here that the figure is at least 2000 years older than the other pieces I showed.


I'm afraid I know little about the tools needed for testing the bronze coloured inclusions other than through a lab. What is a magnitized needle?


As to the debate of whether the carvings are nephrite or serpentine, Ben is having some pieces tested today, including an item from the same batch as the animals, and it will be interesting to have the results.


I am attaching pictures of another Neolithic item. In this case it is carved from a serpentine form, antigorite. We have had this stone tested through QUT; Dr. Cook has also had some tested through the Calgary University. From the pictures you will see that the surface shows a secondary mineral, which has not been identified. The secondary is hard, shows no particular habit, has a metallic sheen in some areas, either black or bronzed. The bronzing shows only in tiny specks on the dark brown to black. The secondary mineral is slightly raised above the surface. The stone itself is silky smooth, where nephrite is fibrous in the weathered areas.


We have tried to get secondary minerals tested through Raman, but it is a very slow process and the price is prohibitive.


This piece is 27 x 20 cm.

12th Jan 2010 22:49 UTCTrish Wilson

more pictures ..............

12th Jan 2010 22:54 UTCCraig Mercer

Someone needs to get in and give that thing a good clean. Do we really need to see anymore photo's of these, I think the general consensus has been seen.

12th Jan 2010 22:55 UTCTrish Wilson

If anyone has any idea of the secondary, would love to hear from you.


Thanks.

12th Jan 2010 23:03 UTCEzekiel Hughes

My posts on other forums are open for all to see and critisize.....unlike yours. No one is my mentor...my opinions are my own. thanks.

12th Jan 2010 23:47 UTCRob Woodside 🌟 Manager

Your C dragon looks a little more Like i would expect . The relief is not that high and the pyrite has oxidized to limonite. Antigorite is a better host for pyrite.


To magnetise a needle rub it against a magnet. When magnetised and suspended by a thread attached to the centre of the needle, it will point north.

13th Jan 2010 01:47 UTCTrish Wilson

Thanks for the help, Rob. A few years ago, when we first saw this type of secondary or inclusion, we had thought of pyrite, but had no knowledge of what it became when it oxidized. The test we had done on the small neolithic figure got us totally confused about what we were looking at.


Also, will try the magnetized needle test on the others.


Thank you, again.

13th Jan 2010 02:44 UTCAlex Homenuke 🌟 Expert

Here I am again commenting on a few items that bother me - my background again is a geologist with several years experience mining and studying nephrite. I do not speak about jadeite.

The first specimen with the pyrite cubes - to me these are phenocrysts which likely formed by a diagenetic process, not the metasomatism that forms nephrite.

The river boulders definitely look like nephrite and the weathering is what I would expect to see. Most of the artifact pictures don't look like this.

I agree with others comments that the level of weathering suggested by the pictures should affect the pyrite more.

I took another look at the EBay nephrite/pyrite from New Zealand - this looks like later emplacement on a fracture - there is alteration along the fracture supporting this observation.

The mention of weathering showing the felted texture of nephrite - an SEM (scanning electron microscope) is required to see texture in nephrite. If coarse enough to see on surface it could still be the tremolite/actinolite composition.

Other inclusions common in nephrite are chromite (steely gray polished) and ilmenite - this could be the resistant brownish patches on the antigorite carving.

I still have not found a reference positively identifying pyrite as an inclusion in true nephrite.


Disclaimer - my opinions only based on pictures

13th Jan 2010 04:40 UTCEzekiel Hughes

A friend was kind enough to photograph a piece of serpentinite he polished with pyrite inclusions. The pyrite didn't come out well, but in one shot you can seen the metallic color....not good close ups I'm afriad. The cluster of black spots are the inclusions....the last show the best capture of the metallic.
http://i790.photobucket.com/albums/yy184/jadadara/SerpPyrite/SerpentinewithPyrite001-Copy.jpg
http://i790.photobucket.com/albums/yy184/jadadara/SerpPyrite/SerpentinewithPyrite002-Copy.jpg
http://i790.photobucket.com/albums/yy184/jadadara/SerpPyrite/SerpentinewithPyrite003-Copy.jpg


When I asked if the serpentinite undercut compared to the pyrite while polishing so that the pyrite stood out he siad yes. He indicated the serpentinite around the pyrite had a hardness around 2 whereas the bulk was harder around 4-5

13th Jan 2010 06:28 UTCBen Peters

Ok, I stopped by the lab today and dropped off a number of pieces, including one of the type posted by Trish. They will test the main material and the inclusions separately.


The results will be delivered to me in about two week's time, and I will post-up then for anyone interested in some part-resolution to the conundrum! I would appreciate some help analyzing the Raman output, as I do not have any benchmark samples.


Many thanks,

Ben

13th Jan 2010 06:56 UTCTrish Wilson

Alex, it is nice to meet you. My apologies if I have been brusque and dismissive at any time -- it comes from mistrust that has built up over a few years. I see you are Canadian, and wonder if you know Dr. Cook who is also a geologist, in Calgary, with the same interests.


Re the boulders -- these are in fact ones that have been loved in Neolithic times, when they were gently shaped into mountains, and then again when they came to light much more recently, and the faces repolished. They are too heavy for me to lift, but I managed to get a couple of pictures using the flash, in a room really not conducive to good photography, of part of the unpolished area where the surface crystals are visible. I thought you may be interested in seeing this.


We have a large collection of Chinese archaic jades, and the variations in the nephrite used is amazing. Not having a background in geology, this is not easy to fully understand or convey. In some cases, where weathering is excessive, the felted texture of the nephrite is clearly visible to the naked eye.


I don't wish to bore the members here with too many pictures of jade artefacts. If you or any of the other members are interested in seeing more and discussing the subject further, I would be happy to oblige privately. jade@scs.brisnet.org.au

13th Jan 2010 08:42 UTCBoris Erjavc

08223240016017609216760.jpg
Specimen on photos "c-dragon - antigorite" looks like serpentinite to me.


Here is one of my serpentinite.


00765650016017609227170.jpg



Boris

13th Jan 2010 09:12 UTCTrish Wilson

Boris, thank you for showing your specimens. The c-dragon is antigorite, which is a form of serpentine.

13th Jan 2010 21:37 UTCEzekiel Hughes

While trying to wrap my head around why one would deliberatly craft a fake with these odd depoits on them I came across this Timelessjade artical...

....The darkened areas shown here are comprised of Manganese deposits and in-situ burial soil that had adhered to the finished piece during its interrment for thousands of years in a burial environment. In the replications, these ‘deposits’ are now usually glued or waxed onto replicas made from a conglomerate of minerals, with burnt-on sugar or black paint ’specks’, to represent the Manganese, and the obligatory mud slurry that seems to accompany almost all faked items. When one is viewing a true artifact, these deposits are permanently adhered to the surface, as they literally become ‘one’ with the burial object and resist all attempts to remove them, short of re-grinding the jade or stone object.....

Timeless jade


of course those deposits are very, very tiny...(see attachment: "Manganese Crystalline Formations Ang Estate Fenghuang" ) ...and sense Trish already confirmed it's pyrite on that piece, that cannot be what we are seeing...and of course shouldn't be carved....rather this neatly explains why someone would try to fake the look...getting a little carried away I imagine.

3rd Feb 2010 01:16 UTCEzekiel Hughes

Alex Homenuke Wrote:

-------------------------------------------------------

> Here I am again commenting on a few items that

> bother me - my background again is a geologist

> with several years experience mining and studying

> nephrite. I do not speak about jadeite.

> The first specimen with the pyrite cubes - to me

> these are phenocrysts which likely formed by a

> diagenetic process, not the metasomatism that

> forms nephrite.

> The river boulders definitely look like nephrite

> and the weathering is what I would expect to see.

> Most of the artifact pictures don't look like

> this.

> I agree with others comments that the level of

> weathering suggested by the pictures should affect

> the pyrite more.

> I took another look at the EBay nephrite/pyrite

> from New Zealand - this looks like later

> emplacement on a fracture - there is alteration

> along the fracture supporting this observation.

> The mention of weathering showing the felted

> texture of nephrite - an SEM (scanning electron

> microscope) is required to see texture in

> nephrite. If coarse enough to see on surface it

> could still be the tremolite/actinolite

> composition.

> Other inclusions common in nephrite are chromite

> (steely gray polished) and ilmenite - this could

> be the resistant brownish patches on the

> antigorite carving.

> I still have not found a reference positively

> identifying pyrite as an inclusion in true

> nephrite.

>

> Disclaimer - my opinions only based on pictures



I got a tidbit of information on the New Zealand occurance some might find interesting...or not:-) but here is the quote from someone I asked from the area:


This stone is an oddity and a unique occurance here in NZ. It only comes from one source, D'Urville Island at the top of the Sth Isld. The area is only accessable by boat and in notoriously dangerous seas. Very little workable material to be found which is probably why not much of it has ever been seen. As Dallas says above, small pyrites are relatively common, particularly in SthWestland stone but not in the size of that example. Cant help you much on the technicalities of formation, but the darkers areas on the stone look to me to be simply discoloured nephrite rather than any other mineral. Not sure about serpentine presence but I know the island was mostly visited in antiquity for its dark tool-grade argillite. Maybe the contact with this caused the unique attributes of this specimen?



The serpentinites in the area are noted for thier high pyrite content, which I guess goes along way to explaining it. I can't afford to pay for journals, so that's all I can find out.


~Zeke

7th Feb 2010 22:09 UTCTrish Wilson

Zeke, you may want to add this interesting specimen to your collection:


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310198308557&ru=http%3A%2F%2Fshop.ebay.com%3A80%2Fi.html%3F_adv%3D1%26_nkw%3D310198308557%26_in_kw%3D1%26_ex_kw%3D%26_sacat%3DSee-All-Categories%26_okw%3D310198308557%26_oexkw%3D%26_udlo%3D%26_udhi%3D%26_ftrt%3D901%26_ftrv%3D1%26_sabdlo%3D%26_sabdhi%3D%26_samilow%3D%26_samihi%3D%26_sadis%3D200%26_fpos%3DZip%2Bcode%26_fsct%3D%26LH_SALE_CURRENCY%3D0%26_sop%3D12%26_dmd%3D1%26_ipg%3D50%26_fvi%3D1&_rdc=1


I would have been interested had it been from China. We have seen numbers of this dark nephrite jade in archaic carvings, however, the percentage that have pyrite inclusions is very small, so the occurrence is rare.


We have not been able to have it tested as yet, but this will happen.


Trish Wilson.

7th Feb 2010 22:15 UTCTrish Wilson

Rob, thank you for your suggestion to try a magnetized needle to test the inclusions in the animal and the jar I've shown in this thread. They are definitely not magnetic.


Trish Wilson.

7th Feb 2010 22:33 UTCEzekiel Hughes

I wasn't entirely convienced that "LEMURIAN BLACK JADE" is jade...haven't found any supporting information except in the metaphysical community...kind of looks glassy to me...but I'll ask around....
 
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