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Posted by Steve Hardinger
Rock Currier December 10, 2013 07:59PMI was collecting artinite up in San Benito Co, California once and it must have been in the middle of a lady bug migration or something, because there were countless thousands of thousands of the little red devils crawling over everything including me. I never thought much of it, but the little suckers can bite! Not bad, but ouch. Got some nice artinite specimens however.
Crystals not pistols.
Edited 1 time(s). Last edit at 12/10/2013 08:01PM by Rock Currier.
Steve Hardinger December 18, 2013 09:07PMBreaking news!
I've just heard some K2 analysis news from John Attard. He was able to isolate a grain of blue material and run EDX. The EDX confirms this material to be azurite. The EDX spectrum is attached.
Thanks, John, for your work on this material.
Now that its composition is confirmed, it's time to debate it's origin.
Steve Hardinger December 18, 2013 09:45PMI should mention that once again John Attard when above and beyond to get this done. He had to tease out a microscopic speck of pure blue material. My thanks again to John for an excellent job! He's my go-to guy for any sort of analytical work.
And now I've looking for more specific locality information. Does anyone have a precise locality for the K2 deposit, or maybe can put me in touch with somone who might have this information?
John Oostenryk December 19, 2013 09:19AMOh Steve, you ol' fakir! What ya got conjurin on the back burner? You aren't switchin to the "dark side" are ya?! Oh Noes! :()?
Just teasin of course, lol...
That is great that Mr. Attard was able to get you(and everyone) a definitive answer. Cool!
As to the second portion: Locale!
~ Back on page 2- Ibrahim Jameel of Khyber Minerals said he had seen a dealer with a big chunk in Skardu, Pakistan, in 2006... I'd suggest dropping him a PM or an email via his web shop. Possibly he could direct you to that contact?
Edited 1 time(s). Last edit at 12/19/2013 09:20AM by John Oostenryk.
Paul Gomez January 16, 2014 06:44AMStephanie Martin Wrote:
> I think it is natural, polishing it brings out the
> intense colour, they do resemble azurite suns but
> until testing confirms it is just a guess,
> although scorzalite does seem to be a better fit.
> Check out photos of rough:
> stephanie :))
Paul Gomez January 16, 2014 07:08AMI am surprised that many people thought that K2 may not be a natural stone... I have found rock while collecting,with similar inclusions that were a reddish brown color and were in a granitic rock.
Edited 1 time(s). Last edit at 01/16/2014 07:15AM by Paul Gomez.
Bill Cordua January 16, 2014 02:42PMPaul - your red areas are probably garnet crystals, and to my eye they look quite different in form from the K-2 blue spheres. In the blue K-2 material you can easily see the underlying minerals through the color - even in thin section. The original minerals are still there - the blue is a penetrating stain, not a replacement of the micas and feldspar. Your red garnet grains have a nice equant morphology against the enclosing minerals, and interlock with the other rock-forming minerals - not at all unusual for the garnets in granite. I do accept that the blue in K-2 is azurite based on evidence presented here, but am still skeptical that the material is natural. No, I can't explain how it could be "faked" but that doesn't mean somebody couldn't figure out a technique. I reserve the right to my skepticism. I look forward to seeing some of this material "in person".
Dan Costian January 20, 2014 03:01PMI would like to inform everybody (who had not in hand this mysterious K-2) that the blue dots in K2 rock are not azurite: the streak is colorless as for sodalite and it does not react as a carbonate when treated with acid.
Dr. James Carter from UTD confirmed that as a fact.
Alfredo Petrov January 20, 2014 05:09PMThe blue dots are a stain on silicate host rock. It takes only a trace of azurite, far less than required to fizz in acid, to make that much blue color. One would not expect to see either fizzing nor a streak. As one of my geology professors warned, "It takes only a penny's worth of copper to stain a whole cliff green and blue, so don't think you've found a copper mine!"
Dan Costian January 20, 2014 05:13PMAlfredo, in my case there are not stains but crystals and the host rock is igneous.
Please see my http://www.mindat.org/photo-587533.html mentioned by Reiner.
My guess is that John Attard worked on a different stuff also called "K-2".
Edited 2 time(s). Last edit at 01/20/2014 05:18PM by Dan Costian.
Steve Hardinger January 20, 2014 06:04PMIMHO...
The blue material is microcrystalline at best; tiny blue specks localized within the matrix so that they appear to be sphere or crystals on cursory inspection.
When immersed in dilute HCl, gas is released from the specimen. Very tiny amounts from across the entire surface (as liquid displaces air pockets in the matrix) but visibly more vigorously from the blue pods. Within a few minutes, all the outgassing stops and the blue pods have been leached.
Sodalite, lazurite, and related suggestions wouldn't give this extra effervescence. Nor would they be consistent with the XRD data.
Of all the guesses made so far as to the mineralogical identity of the blue pods, the only one consistent with all the observations -- and the only one consistent with the best test applied so far (XRD) is azurite.
Azurite has been questioned because the genesis seems wrong. I agree it's weird, but I seem to recall something about the shaving equipment of a certain Occam, and accepting unusual conclusions.
Dan Costian January 20, 2014 06:40PMHi Steve,
My blue stuff on matrix (which I bought as K-2) does not fizz at all with HCl 10%. Maybe we are talking about different materials, I cannot explain otherwise the confusion.
Here is a photo of my K-2 (which I am firmly convinced it's sodalite - besides non fizzing, the white streak and hardness etc confirming it) and below a photo of real azurite (with some red spots of cuprite) concretions on matrix.
Bill Cordua January 20, 2014 07:11PMDan - notice on your upper photo, you can see the original igneous minerals under the blue stain, while in the lower photo the underlying rock does not show through the azurite. This is a significant difference in paragenesis. Your white streak and hardness likely reflects the underlying feldspar. Re the sodalite hypothesis- if the granitic rock contains quartz, then the chemical environment is incompatible with sodalite. Plus sodalite does not form as a secondary stain - it's a high temperature mineral found in alkali-rich silica-poor igneous rocks such as syenite and phonolite. I think also John Attard got an azurite XRD pattern from some painfully extracted tiny grains. If this is natural stuff (you know I still think if) the best hypothesis I've seen is that these are azurite alteration haloes around tiny grains of a primary copper mineral such as chalcopyrite.
José Zendrera January 20, 2014 11:40PMSometimes one insists on something guided by a kind of intuition, and even with compelling reasons against it is difficult to recognize the error. I say this because has happened to me more than once.
The azurite hypothesis has an analisys to support itself.
Has the sodalite hypothesis any homologable evidence?
I think that analitic results are more reliable than a naked-eye examination, even from expert people.
In other hand, there is an important issue which has yet pointed by Bill: sodalite is exclusively formed in alkaline rocks, never in acid rocks as granitoids. Conversely, azurite is not rarely found in granites as secondary mineral.
There is not alkaline rocks around Baltoro Glacier where K2 rock is found.
Trango Towers seen from Baltoro Glacier.
Terrain around Baltoro Glacier is conformed by materials from the Baltoro Plutonic Unit (granodiorites and monzo and leucogranites) with minor zones of gneiss, all of them are acid rocks non-compatible with sodalite genesis.:
These granite mountains are known as The Cathedral, seen from Concordia, the center of Baltoro Glacier:
Here for sure the blue is not sodalite (nor azurite!)
Edited 1 time(s). Last edit at 01/20/2014 11:45PM by José Zendrera.
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Michael Hatskel January 21, 2014 01:52AMFrom what I can see in my specimen of K2, which looks as the same material shown on Dan Costian's photo of K2, the blue coloration is caused by sky blue inclusions in the feldspar grains forming the blue spots. Some of the colored grains may contain one of more of such inclusions in a relatively pale colored feldspar, while other colored feldspar grains are colored uniformly with no visible inclusions and could be from totally transparent to opaque. (When I say "visible", I am talking up to 100x magnification available in my scope.)
I am surprised that there were no microphotographs of the "blue stuff" posted in this thread, so I am posting my own quick and dirty pics taken through the scope ocular. One pic shows separate inclusions, the other shows something like microcrystalline grains of both blue and green color.
I was able to expose some larger inclusions and extract then from the feldspar. When brought in contact with HCl on a white plastic surface, the blue component disappears (gets dissolved) within 1-3 seconds, depending on the particle size. As Alfredo correctly stated (when was he wrong? :-)), the amount of the mineral was not enough to produce visible gas bubbles - again, visible at 70-100x magnification. However, the mineral particles were moving very fast and chaotically inside the acid drop, which typically points to the gas evolution propelling the particles.
In summary, my observations seem to support the "K2 Blue" identification as azurite.
I was actually hoping that it was some copper silicate, based on its residence inside the feldspar.
Some additional comments:
1. The "spots" are actually 3-dimensional aggregates of the colored feldspar grains, not flat 2-dimensional spots.
2. No residual metallic grains were observed in my specimen.
3. No distribution pattern was observed for the spots distribution in hand specimens. I have inspected a full crate of very large K2 rocks, and could not devise any system pattern.
4. None of the bright blue inclusions had any discernible shape: they are basically anhedral grains or flakes or shapeless aggregates.
Reiner Mielke January 21, 2014 05:25PMFrom the micro photos it appears that there is another mineral present besides the azurite. In the second photo I can see turquoise colored patches. Maybe some sort of copper sulphate such as langite? If so that would support the possibility of altered disseminated chalcopyrite causing the spots. It is difficult to imagine the azurite being primary.
Michael Hatskel January 21, 2014 07:12PMReiner,
Those green patches are very rare in my specimen - just in 2 or 3 of the blue spots. All of the coloration is absolutely predominantly blue. I included the second photo just because of the green presence there, but it is not characteristic or widespread at all.
Henry Barwood January 21, 2014 09:50PMAbsent stains of Fe-oxides, a chalcopyrite origin of secondary copper minerals in this stuff is highly unlikely. It might be from alteration of primary Cu containing feldspars, but other than that no other copper source is immediately likely given the nature of the parent rock. The rock is granite, but certainly has alkaline affinities. Would still like to see a picture of the stuff in place in the quarry.
Troy, Alabama USA
Alfredo Petrov January 21, 2014 10:25PMInstead of chalcopyrite, could we be dealing with oxidation of microscopic inclusions of native copper in the feldspar? That would explain the absence of secondary iron oxides.
Metallic (uncombined) copper is soluble in feldspar-rich silicate melts and exsolves during crystallization of the feldspar (as ones sees in "Oregon sunstone" gems, for example).
Edited 1 time(s). Last edit at 01/21/2014 10:26PM by Alfredo Petrov.
Michael Hatskel January 21, 2014 10:32PMHow would the inclusions get chemically altered without the alteration of the enclosing mineral? And how would the CO2 get to it?
One of the possibilities is that the enclosing feldspar is a recrystallized product of the metamorphism which also brought in the CO2 to create a carbonate.
Henry Barwood January 21, 2014 10:57PMAs I said, this is not, petrographically, a "normal" granite, but has alkaline affinities. It probably is similar to a fenite and was subjected to alkaline solutions (Na, etc as carbonate complexes). The sauseritized feldspars indicate that a lot of fluids moved through the rock. Not difficult to go from there to alteration of the Cu-feldspars to what you see.
I can't believe this thread is still stumbling along!
Troy, Alabama USA
Alfredo Petrov January 22, 2014 12:09AMMichael, Any mineral that is mechanically stressed by tectonic movements, rapid temperature changes, etc., can develop invisible sub-microscopic fissures that allow oxidation of inclusions. One even occasionally sees oxidation of pyrite inclusions in quartz crystals, without any fractures that are obvious under a scope, and that can happen even more easily in a feldspar full of incipient cleavage planes. I can't say that's what happened here, only that it might have happened. Study of thin sections might help.
Reiner Mielke January 22, 2014 12:54AMI wouldn't expect any iron oxides if the iron is tied up in a carbonate such as ankerite, maybe we are dealing with altered disseminated chalcocite instead? However native copper would also explain it but how common would that be? No mention of much carbonate in the thin section work that Henry did ( see page 7). I would have expected some other carbonates besides azurite.
Henry Barwood January 22, 2014 01:15AMI did not see any identifiable carbonates in the thin sections, but remember I had a limited set of sample (two slices). I wasn't able to test the amphiboles to see if they were alkali, but there was significant chlorite alteration of the biotite.
Recently Julian Gray of the Tellus Museum in Georgia has discovered interesting carbonates (calcite and REE carbonates) associated with the granites that host the amethyst localities in central Georgia. I have also found significant calcite present in zoisite containing granodiorites from Alabama. Carbonates are likely more common than recognized in granites and leuocogranites.
Troy, Alabama USA
shah March 12, 2014 06:56PMAfter reading all the comments am glad to see such professional people elaborating this mineral.i am basically from Gilgit Baltistan and felt a bit related to this issue as i personally know the main source of this material and supplier which is my close relative. As i have myself possess some samples and we are basically supplying this material through different middle man across the world as per demand. Beside all the research i am planning to bring some sample to Australia for testing and targeting market as we are dealing in different gemstone and minerals.Thanks for all interesting comments and information guys cheers
Ps: these are some pics i have got.It is also known as Raindrop Azurite and jasper k2 azurite(jasper not make sense but its more famous name) and it has some Malachite spots as well in it which i have seen in some of the pieces personally.
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Steve Hardinger March 12, 2014 08:34PMThere is one rather large assumption being made by several participants in this conversation; an assumption that no one has proven (or disproven); an assumption that is a false extension of my original observations.
I stated that gas was released upon immersion in acid, but I did not state the nature of the gas. Perhaps it was CO2 or maybe just entrained air.
Until the chemical composition of the gas is verified, we cannot use its composition as evidence for or against any carbonates.
In addition, I did not say that gas was released from many samples; I tested only one. Perhaps the gas is entrained air, and is not present in all samples.
James K. C. Huang May 23, 2014 06:19PMHi Everyone,
To see a long discussion here, I cannot eliminate curiosity on this interesting rock,
so I obtain a small sample which I did some SEM work to see if we can get some further info on this rock,
and Hope this help to resolves the nature of the K2 Blue.
I found several features of K2 Blue sample:
(1) The blue mineral are found as copper carbonate (azurite) as indicated by EDS data.
(2) Azurite occur as micron sized veins in and around quartz or K-feldspar grains (Size range around 2-5um in width) or as small pockets (5-20um) in plagioclase which I suspect them as dissolution voids formed during hydrothermal alteration.
(3) Plagioclase which hosts void filling copper carbonates has composition close towards albite, which supports Dr. Barwood's observation.
(4) Very minor amount of Sulfur was detected in these secondary copper mineral, makes me wonder the possibility of pre-existing copper sulfides in the rock, which got alterated by late stage CO2 rich fluid event.
Overall, I think it explains why these blue spots seem overprinting the original rock textures of the granitoid, because they formed later than the rock matrix minerals. This can be evident by occurrence as veins and void filling.
Due to very small nature of these blue minerals, it will be difficult to see bubbling reactions with HCl, and it will be hard to tell base on hardness or other physical test.
Lab of Micro-Nano Mineral Science
Department of Earth Sciences
National Cheng Kung University
James K. C. Huang May 25, 2014 02:30PMI was so interested in mineralogy and microtexture of the blue,
even intended to do EBSD structure determination (which would need more time).
But I think so far to all the experts here answered, my result is pointing to the same direction, and I am happy with that.
Thanks Rob, I am happy that I can help.
Thanks for the suggestion Reiner Mielke, I will prepare a better one to put on mindat soon.
BTW, does anyone actually know where it come from??
Lab of Micro-Nano Mineral Science
Department of Earth Sciences
National Cheng Kung University
TJ Taylor April 22, 2016 04:35AMI too have been wondering about the K2 Blue Azurite. There is a California Seller on eBay that have been selling jewelry with that label. It would be interesting to know how they concluded it was Azurite. I included a picture of one of the pieces offered. This seems to be the only seller on eBay with this item.
Alfredo Petrov April 22, 2016 05:19AMThis stuff has been sufficiently well studied now that we can be sure it is: 1) azurite, and 2) natural. I've seen no credible evidence for anything else. As for where it's from, I think somewhere in "Pakistan", vague as that is, and perhaps maybe possibly indeed from somewhere in the general region of the mountain known as K2 - hence the name - but I don't know whether anyone except the miners knows for sure.
Florian Baur April 23, 2016 04:28PMI just read the whole thread and found it very interesting. Thanks for sharing all that information!
Regarding to the origin, there's a post by someone saying he's a close relative to the main (only?) supplier of the material:
For some reason there was no reaction to that post. Maybe the author can be contacted?
Amy June 02, 2016 02:07PMI know this is an old thread but I have tried to find this information in so many places. I have several pieces of K2 and they are all from different and reputable sources. I use them in jewelry and the ones I wear the most, especially those against my skin have turned dark, some almost black. My guess is that it's from my skin's oils. The lighter colors of the whitish part of the granite is so dark it's difficult to distinguish where the azurite begins. Some pieces, the azurite stains have dark streaks appearing on them, in line with the darker grains on the lighter parts that have intensified. Is there something I can do to get these stones back to the original color? Leach my skin oils out? Should I apply a sealant of some sort to the other specimens this hasn't happened to? I am just starting to learn about geology, I'm an autistic woman living in Utah where I find azurite, malachite and granite (not altoghether like the K2) in abundance and can't get enough of it. The look and feel of my K2 helps calm panic attacks in me, don't know why, but it's like a security blanket almost and having my favorite pieces change color on me, is really freaking me out. I'd be grateful for any information anyone can give me. Thank you.
Alfredo Petrov June 02, 2016 02:42PMThe rock must be slightly porous, as shown by the fact that the copper-bearing solutions that deposited the interstitial azurite were able to migrate outwards from their tiny primary precursor grains. If copper-bearing solutions can migrate through it, so can skin oils.
Anything used to remove the oils must not affect azurite. You could try an organic solvent like gasoline, but it might take a very very long soak. This is a case where an ounce of prevention is definitely worth a pound of cure. Best just make sure a sealant is applied to any future pieces you acquire, Amy.
D. Peck June 05, 2016 03:57PMAmy,
I have used diluted epoxy to seal rock chips from which I have cut thin sections for study. In those cases, I soaked the chip for 24 hours, removed it from the solution and heated it for another 24 hours.
I would think that epoxy diluted with toluene (what I used, 5 parts toluene to 1 part epoxy), would work for you. The diluted epoxy soaks into minute voids and cracks that open to the outside. The heating sets the epoxy and drives off the toluene. It does not have to be real hot, just a good warm place will do. I have never used acetone to dilute the epoxy, but I think it would work and it is easier to get. If you try this, be careful with the acetone or toluene, it is highly flamable.
Dana Morong June 06, 2016 05:36PMBe careful about heating anything with epoxy, as burnt epoxy fumes can be toxic. Acetone is so volatile that it can evaporate before one gets the chance to use it, in some cases.
Amy, I was going to send a PM (Private Message) re ASD but you don't have PM (may not be registered on mindat.org?).
Anyhow, enjoy your minerals. They can be therapeutic, but I'd be careful of the volatile chemicals sometimes used in cleaning or treating them.
Anonymous User December 14, 2016 03:44PMHi!
The interesting articles on this stone are:
Hope these will be read-worthy for those who are interested in this stone.
Gregg Little December 16, 2016 05:36AMWIBD (well I'll be damned). As a field geologist who has seen his fair share of rocks from hand lens to petrographic microscope, I followed this discussion with much skepticism. I watched from the weeds to see where this would lead. The most "misleading" curve mother nature threw me was the lack of alteration in this intrusive. After having seen much porphyry copper mineralization one gets use to the classic potassic, phyllic, propylitic and argillic alteration zones and the accompanying mineralizations. This "K2 Granite" is highly unusual in that it lacks any significant alteration. Congratulations to all who beat this one into ID submission.
Ralph Bottrill December 26, 2016 02:10AMYes, it really needs a lot more explanation yet - it seems to be a solid, unaltered granitic rock, wtith no veining, but somehow copper minerals are growing within it and there is no indication of whether its replacing something or maybe infilling some unexplained porosity. If its replacing chalcopyrite then you might expect some iron oxides. I keep hoping to see something published in a refereed journal.
Anonymous User March 10, 2017 12:11AMHi Guys, I know I'm probably a bit late to this post, but I'm really interested to find out your results from the K2 samples. My father works for the local council in Victoria, Australia, and found this sample in a quarry that produces crushed rock for roads in the local area. It seems to have some very similar properties to the K2 rock, but also appears to contain some Iron. With my limited knowledge it appears to have some alteration halos around some quartz like crystal. and there is a significat blue colour which we assume to be azurite. Any ideas? one picture shows a rough side, and the other a polished side.
Gregg Little March 10, 2017 05:43AMMatthew; Your rock is much more altered than the K2 rock. There appears to be quartz (grey) replacing the interiors of the feldspars (pale brown) and there is a darker brownish mineral forming alteration rims around some of the larger crystals as well as altering the ground mass (finer background) throughout. The rusty spots could be oxidized pyrite or other iron bearing sulfide like chalcopyrite which would also source the copper if the blue is azurite.
We'll see what others chime in with but in the mean time try some dilute HCl on the blue mineral to see if it effervesces, under magnification if necessary.
Shah Abbas April 09, 2017 07:19PMThis material is mainly from skardu which is main city (nearest to mine) in Baltistan northern area of pakistan. Somehow mines are far into khaplu valley somewhere and yes it is mined near K2 mountain. not everyone is familiar with this stuff there so only we have main stock of it. This material has been supplied and sold in america in bulk quantity long time ago through a middle man but still alot of this stuff is in market available now almost everywhere. If any of you guys need free samples please feel free to message me as i am going back to Pakistan in May. Thanks for all the detail information on K2 azurite.
steve m johnson April 28, 2018 04:54PMI saw the material in real life just recently and was indeed shocked by the unusual geometry and distribution of the blue stained granite. On polished corners and surfaces I could see there were indeed intact mineral aggregates within the blue field so indeed it was a stain not a mineral...which is strongly affirmed in the blog.
Close look showed the stain was not always controlled by mineral edges or aggregates. Clearly the stain crosscut borders. In posted pictures posted I could see signs of two distinct mineral staining events that seemed exclusive...one, the earlier was cloudy green and looked like several coloration fronts had merged into a larger one with stronger colors clearly present along an irregular and diffuse pseudo bulbous "frontier" with a crude center that appeared depleted of coloration. Apparently superposed on it was the darker blue forming the distinct separate splotchy features. Most of the blue could be associated with tiny dark deep blue aggregations at 5x magnification. The specks seemed irregular and no signs of a radiating or acicular structure were obvious. Blue speck centers did not host any particular mineral and the distribution of small dark granules seemed irregular within the blue color field. Anyone with a dropper bottle of sulfuric acid and a nail could demonstrate the presence of copper with a few drops on the blue field and scratching the wetted spot with a nail or even the tip of a rock hammer. The presence of copper would be indicated immediately by copper plating on the steel. That test seems to have been ignored in favor of many exotic tests some of which showed copper percentages exceeding 1%. Such concentrations of Copper are considered Very high....as mining in Chile, where I work proceeds at levels averaging 0.65% Cu down to as low as about 0.35% Cu. There were no signs of sulfide mineralization in any of the polished specimens I observed, clearly suggesting that we were well within the hematite mineral field but the lack of hematite staining and the presence of quartz, biotite and feldspars were surprising, suggesting exposure was so rapid that weathering had not proceeded significantly. The granites are hard and show no signs of clay or even significant argillic alteration. The granophytric textures exhibit a noticeable foliation in many specimens but with few obvious signs of fractures, veins or other typical signs of resurgent shallow intrusion such as healed straight brittle failure veins or even bent veins that were plasticized through re-heating. Given the presence of the tartan plaid twinning and some of the rock analyses I am inclined to make the case that the granitic material with the blue splotches reflects rapid exposure of the potassic core of a differentiated igneous intrusion that has been so oxidized that sulfides have been entirely transformed to oxide zone minerals. The oxide zone minerals are most likely found as azurite/malachite probably after chalcocite and maybe after primary bornite (!) in my opinion (given the way chalcocite shows up in my area in Chile...tiny spots of roundish sectile material after Covellite after Chalcopyrite).
The apparent lack of sulfides and the lack of any sort of yellow or brown coloration associated with iron staining from alteration of chalcopyrite and other iron phases. The carbonate bearing granitic assemblage appears well within chlorite/propylitic zones and is probably associated with a carbonate rich phase of core potassic alteration.
Carbonate phases are entirely stable within the core of a cu porphyry system depending on the particulars of the geochemical system. In this case, assuming the material represents a magmatic system, which I strongly suspect, the parameters are oxide rich and..apparently...very low sulfidization. The association with porphyry core mineral aggregations, biotite and k-spar without clays or obvious silica flooding is supportive of the chance that intrusive projections...dikes/sills and plugs etc formed where silica saturation was well balanced. The mineral mix may have still been within the solution solubility of the melt. (Veins would be expectable only during strong silica oversaturation.) Because of the lack of veins, the material separated into disseminated metal phases that were not transported much and the material was emplaced in the plastic zone...below the zone of brittle failure.
The apparently simple lithology presented in the specimens posted suggests the K2 Jasper material may be a one event "shoot" coming out of a larger body that has not been recognized yet.. No signs of incorporation of fragments from the larger body within the Shoot are reported or visible in photos but several 1+ cm xtls of k-spar were visible in hand samples suggesting something is present within the magmatic system that we know nothing about but which deserves consideration. The even distribution of small colored grains, green and blue (azurite and malachite probably) ignoring the distribution and extent stained areas suggests the colored grains may very well reflect the remains of so called primary igneous disseminations (probably sulfides) formed during solidification. Overall, the samples suggest the geological exposure of parts of a mineralized system. The presence of muscovite and biotite are consistent with potassic associations and the presence of microcline/k-spars certainly appear diagnostic.
I would attribute the green and then the blue staining to "diffusion" within a "hard" water system at depth. Then, rapid uplift during mountain would change things. My guess is that the system went dry several times during uplift. The dry conditions arrested diffusive ion migration and froze the spheroidal geometry of the leading edge of the stains. The presence of weak hexagonal or pentagonal stain outlines is present but inspection shows the outlines are not obviously associated with mineral edges. I speculate that the outlines may be the result of "mechanical" influences. I propose that the "edged" geometric features visible on some samples reflect geomechanical ion transport. The system I suggest to explain some oddities is the result of some sort of mechanical stress/strain activity, likely during heating and cooling events during crystallization of particular phases underground. Crystallization releases heat right? Anyway, the process I propose in porphyry granite systems undergoing solidification are a shrink/swell pattern that is similar to freeze/thaw cycles that are responsible for "patterned ground" at the surface in relict tundra/cryokarst areas. My bet is that the unusual diffusion occurs in well preserved "porphyry granite" core material with somewhat unusual lithogeochemistry while the hot melt rock is "breathing" a bit.
The distinct dark to light pseudo spherical blue stains reflect the latest ion migration event and from what it appears...that phase was arrested before it dispersed as much as the green tinted cloud-front migration event that is sometimes visible.
I could go on a bit but I want to go buy a few samples to show to my friends and see if they can come up with a better story.
Edited 1 time(s). Last edit at 04/29/2018 12:31AM by steve m johnson.
Gregg Little April 28, 2018 09:11PMThanks Steve Johnson;
I find genesis endlessly fascinating. The apparent oxygen activity in an igneous melt is really unusual especially when we usually think of copper carbonates in the oxide zone of mineral deposits. I am very curious about what your friends will come up with.
Ralph Bottrill April 28, 2018 10:59PMGood work Steve. It’s fascinating stuff, crying out for a serious geological as well as mineralogical investigation. It would be interesting to know the distribution of the material in the igneous body. It usually doesn’t seem to have any typical signs of hydrothermal or supergene alteration, no signs of sulphides, weathering, iron oxides, veining or even fracturing. The azurite appears to be dispersed through a micro porosity that’s hard to explain. You can get native copper extolling as micro inclusions in feldspars, which could explain the lack or iron oxides you get from oxidising chalcopyrite, bornite etc. It reminds me of tourmalinisation in some granites that can form nodular structures during sub solidus conditions, ie. after the granite has crystallised but still contains hot fluids. I had thoughts of doing some thin section studies, but without a site investigation you could only get part of the story and I thought that surely somebody local has visited and is doing some research on it?
steve m johnson April 29, 2018 01:23AMThe existence of native Copper within feldspars sounds strange.
The alteration associated with the K2 Jasper is right in front of your eyes. Thin sections are not very helpful in my opinion but field relatios are. Take some sodium cobaltinitrate and stain the material. Chances are you will not only see the big k-spars get altered but the interstitial material. The ICP work showing a few percent K is strange given the observation of microcline in some thin sections. Anyway, microcline is the key....you don't need much to signal core material is present just a consistent paragenesis showing the right minerals co-exist. It is entirely possible to miss extreme potassic alteration on casual inspection. Biotites and feldspars can look fresh as can be and boom...the rock runs 14% potassium. The potassic zone is typified by biotite and k-spars not argyllization of minerals. Interestingly, the discovery of primary bornite in core is now considered to indicate important things... Whole exploration programs have been started in chile just because of the discovery of primary bornite in "condemnation cores". The discovery is called Escondita North I believe. It was recently reported in a small abstract. For what it's worth, the stability field of carbonates extends to great depth...essentially to mantle or lower mantle depths. Those are the depths of carbonatite genesis...very deep. Phosphates are stable at very deep levels. I am plagued by the presence of microscopic covellite that nobody noticed. I went over core using 30x and 40x and saw stuff that nobody even noticed even though they found big chunks on the surface. After looking things over in plain light at 40x or so Then maybe thin section...but really, in 25 years of mineral exploration, I have never seen much use of thin sections for anything but mineral processing. For example, where I am, conditions are so dry we are seeing blue chalchanthite seeping out of the rocks, probably from a perched exotic copper/supergene deposit sitting at 16,000 ft or so where access is limited. (Strangely, there is as strong a topographic anomaly were I am in Chile as at K2. My property runs to 18,000 ft...and is...you guessed it...right on the watershed crest between Argentina and Chile as are many other mines. Of course, K2 is right on the divide between China and Pakistan. Strange...these hydrological anomalies. There ought to be porphyry systems in the Himalayas.
Regarding tourmalinization....the company Teck has some nice samples from core at one of their mines showing extensive tourmaline is fractures. I have never seen any work relating the existence of tourmaline with actual copper mineral segregation but Borax is good at separating gold from its matrix...maybe tourmaline plays a similar role.
steve m johnson April 29, 2018 01:32AMRegarding carbonate phases. I do not know any primary phase copper carbonates in magmas but there might be some...Look at some of the recent literature and you will find carbonate phases have been added to deep mineral assemblages in published phase diagrams. Carbonates are oxide phases...so is apatite so any melt with excess carbonate might form primary copper carbonates...but I would not be thinking malachite and Azurite.
Basically sulfide rich melts have a solubility for copper that is...what 100x...1000x? Obviously copper carbonates might exist but I do not think the hydrated ones are stable at depth. If a system doesn't have enough sulfur to hold copper the system is expected to be barren. Mafic rock contains much more sulfur than silicic rock by about 100x. The process of separation of copper requires a magma that can soak up and expel its load of metals. I do not think there is much work on carbonate systems so I just have to guess that the disseminations in the K2 Jasper are replacement phases from sulfides. Where I come from you want to see hornblende being destroyed to make a fertile system. The hornblende provides the water and maybe some of the metals. The transformation from hornblende to biotite is one of the indicators of vectoring toward the potassic core. I did notice a few unidentified black minerals within the k2 jasper pieces. I did not take the time to see if they had distinguishable features but if they were hornblendes, I would not be surprised. If they were pyroxenes...I would be very surprised.
Edited 1 time(s). Last edit at 04/29/2018 01:59AM by steve m johnson.
Alfredo Petrov April 29, 2018 12:46PM"The existence of native Copper within feldspars sounds strange."
And, in addition to the one pointed out by Reiner, here are a couple more localities for primary native copper included in magmatic feldspars:
https://www.mindat.org/photo-587489.html (as Matt already noted)
It seems that copper exsolves from feldspar on cooling.
Edited 1 time(s). Last edit at 04/29/2018 12:49PM by Alfredo Petrov.
Gregg Little April 29, 2018 01:42PMI think the puzzling aspect brought to light by the K2 azurite/malachite occurrence is not the presence of copper in basically unaltered intrusive but the presence of hydrated copper carbonates in that intrusive.
One of Steve's very interesting observations is the altitude at which this azurite staining occurs both in his area and at the K2 azurite site. The relative humidity of very cold air can be high. Further, as Steve indicated, field work needs to be done to figure out the deposit's spacial relations. One unanswered question about the K2 copper carbonate staining is whether it is superficial or pervasive with depth. Supergene enrichment at high altitudes could have a whole different character from those typically encountered at lower altitudes.
steve m johnson April 30, 2018 07:51PMMostly high altitude supergene enrichment would be eroded away and only the roots would be left. Is the "K2 Jasper" merely a root? Given the disseminated character of the Azurite/Malachite it does not seem consistent with downward migration. I would expect to see sulfates somewhere. Question...can anyone find "barite" or "tourmaline" crystals in the mix. I would expect discovery of such minerals to be indicative if not diagnostic of a deep source for the rock matrix. Tourmaline and barite minerals would be consistent with the unusual azurite/malachite material at hand representing carbonate altered replacement of disseminated primary mineralization found in the potassic core of a mineralized system whose outer shells have not been recognized or found.
Thin sections would be OK but I bet you could find black specks of tourmaline in that rock at 40x. Polished faces should eventually reveal the existence of some sulfide...but if that sulfide is covellite and blue...you might not even see it. Careful examination might show the paragenesis of azurite after covellite after ....bornite. Usually covellite suggests high sulfidization but in fact, covellite can form surficially. It has been identified as a kind of "rust" on some tools.
For what its worth, eroded out supergene material does not go away. The copper does not just disappear, it can and has be captured naturally and accumulated as "exotic copper accumulations". I think there are several places where that has taken place where I work, except it is Digenite way up high, flushed out down where the drill roads are as chalcanthite. Wish my project area were lower and not half a world away but then someone else would have grabbed it before me. Anywhere there are several examples of folks failing to recognize the potential of "exotic" copper concentrations in the literature but one interesting one has to do with Richard Sillitoe's recommendation to explore a flat area adjacent to an active mine, probably in Chile. On his say there was a lot of supergene copper discovered at shallow depths in the flats using blast hole drills. Apparently geologists and mine personnel had driven past the deposit every day for some 60 years without even thinking about the possibility.
Attached is an example of the covellite after chalcopyrite from an online image, the other image shows my area with what I have evidence of... a perched supergene deposit.leaking abundant blue copper mineralization from space shots. On the ground .we identified lots of blue stuff in the field as calcanthite probably after chalcocite or possibly supergene digenite. Some samples in the field ran 69% Cu!.
steve m johnson May 01, 2018 12:30AMyes it is.......and this is not even the Atacama...it is on the edge.
Like in "farewell to tarwathy" by Judy Collins....like the cold coast of greenland....in Chile
the winds blow through passes that are three miles high...
but the air is so thin it is as worthless as breathing the sea
there are no song birds in Chile to sing to the whale....and there is no habitation for a man to live there
but we all hope to find riches a hunting the whale.
steve m johnson May 01, 2018 06:27AMProposed K2-Jasper source: Google earth imagery around K2 shows no mining no access, only graywacke, ice and rotten black sooty ice glaciers. Some distance away where the rotting ice becomes a braided stream/river there is a forward camp called Jhola. There is no road access there but it may extend up to within a few miles before the road gets cliffed out. At Jhola there are two helipads and lots of signs of activity. Ground photos show some interesting things...but the main thing is that there isn't all that much granite to be had in the whole K2 area. Most of the area is made up of ice and greywacke. The glaciers and rock faces are positively black in those areas. Where you can actually see white material we have the Baldu pseudo river all rotten ice and black sooty covering, but on the edges there is a distinct morainal train of white granite that makes up the sides of the rotten ice glacier. Along the cliffs there are extensive signs of granite intrusion along with some interesting iron stained units and some rounded pebble "cataclasites" in bedrock along with some walkers approaching Jhola. I'm betting the riverbed contains some of these dew drop azurite rocks and that there are other places where folks have just hand picked the stuff. No sign of excavation can be found anywhere really. It's always possible that the dew drop rocks are actually fragments from within the reddish cataclasite in the foreground. Trails lead off from the camp itself and go all the way to ice. Upstream of the camp there are several miles of white river bed alluvium with big granite dikes and sills on the canyon sidewalls. As you approach Jhola camp you can see lots of interesting lithologies in rounded river rock and on the cliffs. Where exactly that blue stained material comes from is a mystery but I'll bet if you were there you'd find its source. My bet is that all the interesting stained material in circulation is virtually hand cobbed and hand carried from within a few miles of Jhola camp to road end. All that fresh leucogranite sure looks like the parent material of the so called K2 Jasper. I can't figure out the mineral system but my guess is that it represents dike material from the larger body intruding the system. Obviously where there is so much glaciation there isn't much chance of seeing other facies of the hydrothermal/magmatic system but you can probably find a little here and there in the fines.
Alfredo Petrov May 01, 2018 07:07AMWe might have to look at a wider area. We are only told that the locality is "near" K2 and there's a lot of fuzziness built into the word "near". I've heard the word "near" used before for a mountain just because one could see it in the distance ;))
José Zendrera May 01, 2018 10:57AMWhile the exact location remains a mystery, after reading many information available about this material and knowing personally the Skardu area, I tend to believe Shah Abbas in his message above in this thread: K2 blue dotted gneiss comes from Khapalu area, 60 Km east from Skardu and 80 Km south from K2 peak.
steve m johnson May 03, 2018 06:28AMAnd here is a nice granite intrusion for you all. Perhaps you will notice it is a photo of K2!. It is the best I could find that appears to clearly show white granite wth a shell of greywacke.... the geology of K2 appears to be a big granite spire. Looks a bit like something in Patagonia. I saw another set of granite spires at nearby Trango Towers just upstream of the last set of images along Bailto River(sic)...if I got the name right. So, we have another little piece of the big picture. I noticed that K2 sits in a strange structural/topographic position...astride the margin of a 10 mile wide, I guess large, semicircular Subsidence feature. I like to think of the geomechanics of a toothpaste tube that got dropped on the floor and stepped on. The weight of the downdropped subsidence feature skooshed the underlying material and up popped K2...right on the edge along the detachment Surface itself. So there are granite apophysees to be found! Next thing we know someone will post an image of the source of this dew drop rock and it's potassic alteration suite and I'll have set off another "gold rush"...my third. Sigh.
Frank K. Mazdab November 06, 2018 02:03AMHi Tim,
I analyzed it... it's my thin section FKM-105 (https://www.rockptx.com/fkm-101-to-fkm-125/#FKM-105).
The blue sunbursts do contain tiny scattered azurite, but not very much. If one looks closely, it's possible to see tiny darker blue specks within the larger blue sunbursts. Those tiny blue specks are the azurite.
As for the rest of the blue material, most of their volume is a fine-grained admixture of albite+quartz with a combined copper content of ~1200 ppm Cu. Because the albite+quartz mixture is intergrown on a such a fine scale (1-5 microns, comparable to that of the microprobe beam diameter), it was difficult to get an albite-only (or quartz-only) analysis, although from the BSE imaging the mixture in my sample appeared to average about 70% albite & 30% quartz. So it's unclear if the 1200 ppm Cu represents solid solution in the one of the minerals, or alternatively the presence of some sub-micron discrete Cu mineral (more azurite?; chrysocolla? something else?) just not visible in the BSE imaging. In any case, that small amount of Cu, whatever its nature, along with the scattered tiny azurites, are enough to color the sunbursts.
What's also interesting is that many of the minerals present contain measurable Cu: muscovite & biotite (~450 ppm Cu), chlorite (~1000 ppm Cu), titanite (~650 ppm Cu) and epidote (Cu not yet measured). There was no evidence of a pre-existing Cu sulfide to source the azurite and other Cu enrichments, although it's possible it was there and was just obliterated during low grade metamorphism or propylitic alteration and then redistributed into the minerals present now.
Edited 1 time(s). Last edit at 11/06/2018 02:18AM by Frank K. Mazdab.
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