Learning Center What is a mineral?The most common minerals on earth Information for Educators Mindat Articles The Elements The Rock H. Currier Digital Library Geologic Time

Minerals by Properties Minerals by Chemistry Advanced Locality Search Random Mineral Random Locality Search by minID Localities Near Me Search Articles Search Glossary More Search Options

The Mindat Manual Add a New Photo Rate Photos Locality Edit Report Coordinate Completion Report Add Glossary Item

Mining Companies Statistics Users Mineral Museums Clubs & Organizations Mineral Shows & Events The Mindat Directory Device Settings The Mineral Quiz

Photo Search Photo Galleries Search by Color New Photos Today New Photos Yesterday Members' Photo Galleries Past Photo of the Day Gallery Photography

Discussions

💬 Home 🔎 Search 📅 Latest

╳Discussions

💬 Home 🔎 Search 📅 Latest

Groups

Recent Images in Discussions

Identity HelpReal turquoise?

13th Apr 2013 06:25 UTCMeems

Super newbie here. I've always loved turquoise and this necklace called my name today! I have never seen turquoise like this. I was assured by the seller that it was real turquoise. I brought it home and tried the hot pin test. Nothing happened. No smells, no smoke, no burning, nada. I tried 5 different stones. I can see the holes on some of the stones and they are not white inside. I'm afraid to soak in acetone since there are some tiny little beads between the turquoise that I fear might be ruined. Also, I am okay with wearing it even if it's fake or stabilized turquoise.

It's rough to the touch in some areas, no smell to it at all. I apologize for the photos. All I have is my phone camera so I tried to use my bright light to help with focus and detail. It was hard to get a good, clear close-up of the center piece! Thanks for any help! I am loving this site.

13th Apr 2013 09:54 UTCRock Currier Expert

Turquoise is a real mess. I don't think it is possible by looking at it to determine if it is "real" or not. When your supplier said it was real turquoise you should have asked him if it was completely natural and untreated turquoise. If he didn't dig the stuff out of the ground and make the beads himself there is almost a certainty that there is any way he could know that they were completely natural turquoise. The hot needle test at least eliminates a a couple of the the more obvious treatments.

13th Apr 2013 12:17 UTCOwen Lewis

Hi Meems,

The bad news is that the great majority of turquoise that reaches the retail market has been treated in at least one and maybe more than one way. - and that's ignoring all the 'imitant' stuff. If you like the item (it looks pretty) and you did not pay an arm and a leg for it, then have done, call it your turquoise necklace and enjoy it:-)

FWIW, the colour of the stones seems to vary a lot; IMHO that makes it *more* likely than not that they are not man-made or an imitant or dyed. Whether they have been 'stabilised' can't be guessed from a pic - but almost all is these days.. The 'beads' between the stones could be a number of things - including plastic.

If you are still curious, you can do a basic check for dyeing as follows. Dip the cotton bud in a bottle of acetone. Quickly touch the bud to a piece of absorbent paper to take of any acetone just waiting to drip out of the bud and run everywhere. Rub vigorously an area of one of your stones (away from the beads!) for 4-5 secs. If blue colour comes off onto the white cotton bud then the materal is dyed. However, if the stones have also been stabilised, this simple test may not always work.

Another tip before you try the acetone test. Touch a stone to your lips. Does it feel warm or cold? If cold, you have a mineral of some sort and if there is no cold sensation, it's probably plastic. Try this with a couple of 'known' polished stones and a piece of known plastic before you test the necklace, so you know the difference in sensation you to expect.

Me? I think I would just enjoy wearing it!

Good luck.

14th Apr 2013 19:43 UTCTim Jokela Jr

No way to confirm treatment or lack thereof from a photo.

The color is a bit weird to my eye.

I think you can safely assume that it's treated in some way or another, like emeralds.

The only turquoise I'd really trust would come from the guy who mined it, and I'd expect to pay a bundle for it.

It'd be cool if you could de-string a bead and saw it in half.

I wonder what's inside!!!?

In cases like this, it pays to do business with a highly trained local jeweler, who keeps up on the latest simulants by taking courses every year, that you know and trust.

14th Apr 2013 20:31 UTCDon Saathoff Expert

Meems, if you bought the jewelry because you like it and plan to wear it, what does it matter if it's turquoise or chrysocolla - they're both beautiful stones. If untreated turquoise is not cleaned & handled properly, exposure to natural skin oils will soon darken it - I would prefer treated turquoise! If you bought it to re-sell, THEN you MAY want to know the details, but, for me, jewelry is ultimately valued by how much you like it, regardless of what it is!!!

Don

27th Aug 2013 10:30 UTCgeorgia reynolds

Hi

I agree with Don.

I have been testing for years, with some of these materials that are coming out it is hard to tell.

Do not forget that even most sapphires are treated now.

I like my stones to show their inclusions that shows me the path of the stone. It is it's birth mark so to speak.

Buy what you like and only pay the price your mind puts on it. Otherwise buy from somebody who knows what they are doing and is willing to give you a certificate to say your item is natural.

Best of luck

Georgia

10th Dec 2014 18:51 UTCMargaret

Hi, I need your expertise. I am helping a friend trying to sell his Aunt's estate (92 years old). This woman was a collector of different stones. Coral & turquoise being two. I have her turquoise necklace - it is cold to the touch & remains that way & heavy. I tried the acetone test no color came off. Did not try the hot pin test, as I'm sure I would have ended up burning myself in the process. I think this was in her prosession for the last 30 to 40 years. Is there a reason to think this is authenic turquoise and of any value. I look forward to any advise you could give me. Regards, Margaret

10th Dec 2014 19:09 UTCReiner Mielke Expert

Too blue for turquoise (assuming the color balance isn't way off). Azurite maybe?

10th Dec 2014 20:24 UTCOwen Melfyn Lewis

I agree, not turquoise. Plastic would be my first guess just from appearance (yes, even 30-40 year old). I had the dispiriting task of sorting out my mother's jewellery after her death, much of which was bought during tourist jaunts to different parts of the world.

14th Dec 2014 00:21 UTCturtledove thrushe

Too blue to be Turquoise unless the colours are not calibrated on the camera. Could be dyed or could be plastic. At this point I agree that it is something else.

14th Dec 2014 01:05 UTCAlex Earl 🌟 Expert

At first I thought it was Lapis Lazuli because of the color, but upon closer examination it looks like some sort of plastic, but it is definitely something dyed.

14th Dec 2014 02:56 UTCJacob Helton

The color and the lines cris-crossing in the material look a lot like so-called "blue howlite" sold by a lot of online bead retailers.

14th Dec 2014 12:41 UTCJosé Zendrera 🌟 Manager

I agree with Jacob, it really looks like dyed howlite http://www.mindat.org/min-1936.html which is widely sold as turquoise http://www.mindat.org/min-4060.html ersatz.

Please see:

https://www.google.es/search?q=blue+howlite&biw=1636&bih=1316&tbm=isch&tbo=u&source=univ&sa=X&ei=6IKNVJS4N8b3UpOfgoAP&ved=0CCcQsAQ

http://en.wikipedia.org/wiki/Howlite

1st Mar 2015 14:37 UTCSobia

That may be a Turquoise, but a saying goes, that when the turquoise turns green, throw it away.

Turquoise comes in Red too. But green is definitely a NO.

1st Mar 2015 18:08 UTCsteven garza

Dear Sobia;

Understand, that nearly ALL turquoise, as time goes by, turns green; it's not fake, the copper just is making a different response. Since nearly no "turquoise" is really turquoise, but one of several Al phosphates that naturally have some Cu mineral inclusion/Cu substitution; this topic was brought up, on another thread, earlier that stated, that a study done on many "turquoise", from many classic American sites, was NOT turquoise. That's why it's going to be difficult to prosecute many dealers for calling THEIR obviously fake stuff, bcs, stuff we've been calling "turquoise, for hundreds of yrs., isn't either. Now, it's more a jeweler's term for a whole group of Cu bearing minerals that are amorphous & used for jewelry.

BTW, water exposure & air infiltration, over time, are the culprits for the color change.

Your friend, Steve

2nd Mar 2015 01:53 UTCOwen Melfyn Lewis

steven garza Wrote:

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

> .......Since nearly

> no "turquoise" is really turquoise, but one of

> several Al phosphates that naturally have some Cu

> mineral inclusion/Cu substitution; this topic was

> brought up, on another thread, earlier that

> stated, that a study done on many "turquoise",

> from many classic American sites, was NOT

> turquoise. ....

So.... what do you say it the only 'real' turquoise Steve, and underwritten by what authority? Please see http://www.mindat.org/min-4060.html before responding. It's hard to see any of your claims reflected in that outline.

2nd Mar 2015 02:32 UTCAlfredo Petrov Manager

Owen, I think what Steve means is that the gem definition of turquoise (which of course long predates current mineralogical species boundary definitions) can include materials that aren't technically "turquoise" in the mineralogical sense, because the mineralogical species definition has Cu dominant in the first formula position, but many gem "turquoises" don't have quite enough Cu, and much of their first formula position is occupied by Fe or vacancies ("◻"), making them "cuprian planerites" or other species.

The same situation exists with other gems/minerals, like jadeite for example. I'm certainly not recommending that gemmologists post facto change the names of ancient gems just to "keep up" with the latest mineralogical species nomenclature; it is far easier to just recognize that definitions can vary slightly between different fields and leave it at that. There is no reason at all in my view to change the name of a gem just because it slightly crosses over some arbitrary chemical boundary, while stil maintaining the same color, hardness and other desirable physical characteristics - That would be stupid from a gemmological perspective, but not from a mineralogical one.

2nd Mar 2015 09:47 UTCsteven garza

Dear Owen;

Since the thread has been on jewelry type turquoise, that IS what I was referring to; not the MINERALOGICAL specimens, of xls, especially. Sorry, I should have made that more clear. True turquoise, in lapidary, for CENTURIES, is VERY rare; they didn't use XRDs etc., even when they had them, for the longest time, which are about the only way you can define what is what, anymore. Only recent work, on hundreds of specimens (without damaging them; something else that stopped previous research into the matter) has shown NO American turquoise, mineralogically, in any jewelry. Since planerite & the rest of the turquoise group (a GOOD sized group) all have similar characteristics/workability/color range, telling the difference, by the most experienced eye, just can't/shouldn't be done; as Alfredo pointed out & I've mentioned, on other topics, the mineralogical definitions aren't always in tune with the lapidary/gemological ones - many times by a long stretch.

Your friend, Steve

2nd Mar 2015 14:53 UTCOwen Melfyn Lewis

Hi Steve,

You still do not say what you think "real" turquoise to be. I cannot make sense your suggestion that it is an aluminium phosphate (when it need not contain aluminium) or that copper may or may not be present in turquoise. Come on, chum, what *is* your idea of the "real" turquoise?

@ Alfredo,

You make some good points but please consider.

- Turquoise is a mineral group name (as is also tourmaline). Gemmologists sometimes (e.g. turquoise and tourmaline) find using the group name much more useful for general purposes of trade regulation that fussing with the mineral species and their Heinz57 mixes.

- Within the group there is appreciable difference in the chemistry, structure and colour of what make be properly called turquoise.

- In the main (or completely?), turquoise is one of two (or possibly a mix of two?) binary solid solution series, plus the inevitable impurities that nature provides.

- Some thirty years ago, the great chemist, crystallographer and gemmologist, Dr Kurt Nassau (writing in a gemmological context) described turquoise as 'an aggregate of minute crystals of copper aluminium phosphate hydrate CuAl₆(PO₄)₄(OH)₈.5H₂O, and made the point that turquoise is idiochromatic as a result of its copper content. A bit more prescriptive that the current mineralogical definition but perhaps nothing to argue over, 'Gems' used the same formula but with one less water molecule, pointing out also that FE is often associated with the chemistry. There is a very informative chapert in 'Gems) on turquoise, as I am sure you know.

From a gemmological perspective:

- Identification tests for turquoise are unusually weak, none being diagnostic. It may not be possible to distinguish with certainty high grade synthetic turquoise from the geologically formed. However, according to CIBJO (2013), synthetic turquoise is not now to be found in the market.

- The nondestructive tests of visible spectrum, microscopic examination and SG are the most commonly used

- Turquoise has no useful Raman signature but if a specimen (natural, synthetic or fake) has been polymer impregnated, this has a clear Raman signature.

- Most common sources of gem grade natural turquoise are the US, Iran and Egypt (Sinai) with an interesting and valuable minor source in Uzbekistan. Persian turquoise is graded into three main qualities with different visible characteristics

In sum - and as Rock said right at the beginning, turquoise is really a bit of a mess. As a gemstone, it is common but of limited importance. Most testing effort goes into the detection of fakes and treatments, with not too much concern, perhaps for exact chemistry of any given specimen.

2nd Mar 2015 20:26 UTCsteven garza

Dear Owen,

My idea of turquoise (no quotes) has been, is, & will always be the mineralogical one; as long as I deal in minerals, that's the one I'll discuss.

SINCE, we were discussing GEM turquoise, although I'm not much for gemological terms for "x" material, & since YOU haven't suggested another we could use, that everyone could agree with & use, for lack of a better way of communicating about said material, that's what I used those terms - I guess I'm adaptive to that sort of thing. Since, apparently, the use of that term PREDATES with fixing of it's formula, I'd say that WE may be misusing that name; maybe the turquoise WE know by it's present formula need to be changed (our term being the "youngster" meaning); what's do YOU think?

Your friend, Steve

2nd Mar 2015 20:52 UTCReiner Mielke Expert

Turquoise and Tourmaline are group names but unlike tourmaline, there is a species called turquoise.

As for the remark " Only recent work, on hundreds of specimens (without damaging them; something else that stopped previous research into the matter) has shown NO American turquoise, mineralogically, in any jewelry." I find that highly unlikely as that would imply that there is no turquoise (the species) at the hundreds of localities for turquoise in the US listed in Mindat !

2nd Mar 2015 22:35 UTCPaul Brandes 🌟 Manager

If that's the case, then it surely begs another question...... what does a real turquoise look like? :-S

3rd Mar 2015 00:01 UTCDoug Daniels

Turquoise is obviously a figment of our imagination - like the Yeti, and UFOs, and smart politicians.

3rd Mar 2015 00:33 UTCAlfredo Petrov Manager

Doug writes in jest, I think, but he may not be too far off the mark: genuine turquoise (the mineral species, not the group or gem name) seems to be rarer than collectors and miners think. The late Dr Eugene Foord, mineralogist at the U.S. Geological Survey in Denver, was a specialist in the turquoise group and he was telling a group of us once how the majority of the "turquoises" he had analyzed were really planerites including, he said, even much of the classic material from Iran, at which point Rock Currier interrupted him and said, "Well, Gene, given the historical precedence of the name turquoise, shouldn't "planerite" be called turquoise, and the Cu-dominant material be called something else?" ;-) Foord appeared stumped.

3rd Mar 2015 01:00 UTCWayne Corwin

So can we trust turquoises crystals to be real turquoises :-S

3rd Mar 2015 01:23 UTCsteven garza

Dear Wayne;

YOU GOT IT! THOSE are probably the only COMPLETELY turquoise turquoise there is. During the xlization process, it would likely have a fairly stabile composition, apart from other turquoise group members, which would settle at differing rates; the nodules & veins, being amorphous, probably came out of solution SO fast, they never got a chance to properly separate & form individual xls - I guess you could say they became "turquoise group member soup".

Your friend, Steve

3rd Mar 2015 01:23 UTCAlfredo Petrov Manager

Yes, Wayne, relax ;-)

The RRUFF page for Lynch Station turquoise crystals shows it being pretty close to the Cu end-member.

3rd Mar 2015 01:50 UTCWayne Corwin

Oh Good, I didn't want to have to relable them ;-)

3rd Mar 2015 03:02 UTCDoug Daniels

So, should we tell the Native Americans that use turquoise in their jewelry that it's really not turquoise?

3rd Mar 2015 03:35 UTCPaul Brandes 🌟 Manager

I wouldn't Doug. Custer tried that once and I hear it didn't turn out too well......

3rd Mar 2015 04:55 UTCDoug Daniels

That's kinda what I thought too....

3rd Mar 2015 14:05 UTCJamison K. Brizendine 🌟 Expert

This is an interesting discussion….

When I was briefly at Western Kentucky University, we received quite a number of specimens from the Dos Pobres Mine in Arizona. The specimens we received contained veins of an unknown mineral we thought were turquoise.

We ran a bunch of samples in our XRD and to our surprise all of them registered as aheylite. We had our doubts, that this was aheylite, so some of the poorer samples we “spiked” with quartz, just to make sure our machine wasn’t taking a faulty reading. The XRD again read the quartz without a problem, but with the unknown mineral, it was still reading aheylite.

Just to confirm our findings, we sent the samples to a laboratory at the University of Kentucky. UK’s laboratory had deduced that these samples were a positive reading for turquoise, but the peaks it showed also had a very close match to both planerite and aheylite as well.

3rd Mar 2015 14:33 UTCOwen Melfyn Lewis

Steve, you are baffling me.

You talk of a 'real turquoise' and as 'true turquoise which is very rare' but decline to specify what you mean by this. You also say that 'recent work' (whose?) on hundreds of pieces' that 'has shown NO American turquoise, mineralogically, in any jewelry.'

Without explanation, that comes across just as a load of old cobblers ;-)

I have a cabochon piece of turquoise (with some quite attractively included matrix) from Kingman County, Arizona. I'll guess that there are a million+ other pieces of jewellery where the turquoise is of US origin. Or do you mean that turquoise is not found in the US (though most of us think it is). Again, to make sense of this you really do need to share with us what you think is the 'real/true/very rare turquoise' and where it is found,

If you mean that triclinic translucent monocrystals of turquoise that are large enough to be visible to the naked eye are rare, I could agree with you but, though pretty under the microscope, these are of little gem (commercial) interest. But even these are to be found in the US (Lynch Station, Virginia, I believe). The gem interest is in the aggregated form of such minute micro crystals that has an opaque/near opaque character. Like some other materials (e.g. lapis lazuli) the mineral composition is not fixed but varies within certain limits. The variable composition leads to some specimen being more attractive than others and, hence, also more valuable.

The USA is a leading source of turquoise for the gem trade, though little of it is considered to be of the finest grade. Historically, top grade Iranian turquoise is considered to be the best. Most of the turquoise deposits around the world (including those in the UK) are not considered to be of gem quality.

The standard trade reference book for the jewellery trade is 'Gems, their Sources, Description and Identification' (now called just 'Gems' from the current 6th edition). As said already this gives the US (esp. the south-western states) as a prime source of gem grade turquoise.

3rd Mar 2015 18:22 UTCD Mike Reinke

I don't get it Owen. With all due respect, I thought Steve was quite clear, rank amateur that I am...This has been an interesting discussion, and I am going to footnote my turquoise labels, at least note them now as "turquoise", with quotes.

Also, I passed on a chance to get a Lynch station Va. turquoise last year, and now that I have a microscope, I regret that...

Thanks for everyone's input.

Mike

3rd Mar 2015 18:45 UTCOwen Melfyn Lewis

OK Mike, glad it's clear for you. So will you be kind enough to share the what and why of the only real turquoise, true and rare, and never found in the USA? As for me, I'm feeling about trying to get the sand out of my eyes :-)

Yes, pity about that Lynch Station turquoise monocrystal that escaped you. I'd very much like to capture one of those myself - from any location.

3rd Mar 2015 20:42 UTCsteven garza

Dear Owen;

You seem to be having trouble separating "-ologies", which, in the very quote you used, DOES explain what I mean; what you need, is a sit-down", with someone you trust, who can make better sense of what I'm saying. Apparently, I'm not capable of expressing this in a way you'll absorb; my bad.

Your friend, Steve

3rd Mar 2015 21:31 UTCOwen Melfyn Lewis

Won't wash, Steve. Now, you want to say what you think is 'real turquoise, true and rare, and never found in the USA'? Your words, in the record and not mine.

And it's nothing to do with 'ologies'; just spit it out.

3rd Mar 2015 21:45 UTCDon Saathoff Expert

Crystallized turquoise is relatively rere but does occur is several locations - we have two here in New Mexico, the phosphate portion of the Tyrone mine, Grant Co. and the Bob Montgomery claim in Granite Gap (San Simon Dist.) in Hidalgo Co. We have a couple of samples in the collection from these locations and, yes, they are confirmed turquoise but certainly not gemological turquoise. We should, by now, realize that there is a difference in perception within our hobby. It's not as simple as "rocklickers" or "rockknockers" - there must exist some fence jumping with appreciation for the views! We do have some magnificant turquoise in the collection - suitable for whatever a lapidarist would want to use it for. I DON'T CARE if its the not the same composition as my crystalline material - it's still turquoise!!

Don S.

3rd Mar 2015 23:04 UTCRock Currier Expert

The reality is that mineralogical turquoise is going to be those little crystals from Lynch Station, VA. Namely that copper phosphate. Some time ago I think remember looking into the composition of the turquoise from Mashhad, in eastern Iran (2000 + year history) was predominately also that copper phosphate

However in the greater reality of the world, any blue stone set in jewelry made by Indians (even Asian Indians) will be called turquoise and no matter how much we may rant and rave about it, this greater reality will almost certainly never change in our lifetimes.

When talking about turquoise with someone we only need to ask enough questions to understand which reality they are coming from in order for polite communication to flow. Its very much like trying to settle on the definition for jade.

4th Mar 2015 00:01 UTCOwen Melfyn Lewis

Don, Rock,

The mineralogical view is that turquoise is either of two binary solid solution series that form triclinic crystals, right?

Rarely, such crystals are large enough (say 100 micron+) to see with the naked eye, right? But most times the crystals are smaller, requiring a microscope to identify them individually, right? These minute steep triclinic crystals form massive aggregations that are widely cut up and polished into pieces some cm+ across, to be used for ornamentation or set in jewellery.

How can does crystal size or crystal aggregation determine whether or not the mineral is turquoise? I don't think it does. Are calcite or aragonite any other species just because their crystals are minute and aggregated? I think not. What then is particular to turquoise for some to suggest that an aggregated crystalline form is in some way not 'real' and must be something else? A (say) 5mm monocrystal of turquoise may indeed be a rare form of turquoise but, methinks, that is all it is.

4th Mar 2015 01:26 UTCReiner Mielke Expert

So if the photos in Mindat are mostly not the mineral turquoise them why are they under the mineral turquoise? Does this not just perpetuate the myth of turquoise? Maybe ( unless confirmed) they should all be moved to planerite or ?

4th Mar 2015 06:21 UTCAlfredo Petrov Manager

A lot of the trouble and misunderstanding on Mindat with this type of discussion is caused by differences in terminology between the gem people (mostly Owen), and the mineral people (most of the rest of us); it's like people talking past each other in foreign languages. Poor communication skills on both sides. We really need to understand and accept that names have different meanings in different fields, even closely related fields. Turquoise is a good example: Not all gem "turquoise" is the mineral species "turquoise", and not all of the mineral species "turquoise" is gem "turquoise". There is a lot of overlap, but they aren't exactly the same. "Jadeite" is another example of the same problem.

The first step in reaching an understanding or consensus is to admit differences in usage do exist, and that that is not necessarily a bad thing or an "error". Without that recognition, all discussion is hopeless and we might as well devote our time to more profitable issues.

Reiner, photos end up placed under "Turquoise" because either: a) they look like turquoise; or b) they've traditionally been called "turquoise" in the past. Are they really all turquoise, correctly identified? .....Without reliable detailed analyses, we'll never know. (Which is pretty much what one could say of most photos of most minerals ;-) )

4th Mar 2015 11:54 UTCDavid Von Bargen Manager

From the discussion section of the Foord-Taggart paper

" Light blue or blue-green 'turquoise' from

many world-wide localities is actually planerite

rather than turquoise. Pure or nearly pure

turquoise is quite rare as well, and the mineral

from the Bishop mine, Lynch Station, Campbell

Co., VA, is the best high-purity, well-crystallized,

highly Cu-substituted turquoise (e.g. Schaller,

1912) that we examined. A re-determination of

the density of the turquoise that was analysed by

Schaller (1912) was made using methylene iodide

diluted with acetone: Dobs = 2.86(1); Dc~lo = 2.91.

Some material from Lynch Station is intermediate

between turquoise and chalcosiderite, and a few

samples of chalcosiderite were found as well in a

batch of assorted samples from the mine (J. Nelen

microprobe data, 1984, pers. comm.)."

http://www.minersoc.org/pages/Archive-MM/Volume_62/62-1-93.pdf

4th Mar 2015 18:35 UTCReiner Mielke Expert

Hello Alfredo,

I understand that similar issues exist for other minerals, however, unless I am misunderstanding this the chances are very good that most of the photos of massive turquoise in Mindat are planerite. Therefore to me it would be logical to place them under planerite and not turquoise (unless proven otherwise). Another better option would be to move them all to turquoise group. This also raises the more important issue of the localities for turquoise, is turquoise even actually found at all these localities or is it mostly planerite? Maybe turquoise should be deleted and replace by turquoise group ( unless proven to be turquoise). Leaving things as they are only compounds the error.

4th Mar 2015 20:32 UTCAlfredo Petrov Manager

You're right, Reiner, and I would not object to moving material from localities where it's never been analyzed to "Turquoise group".

5th Mar 2015 03:49 UTCRock Currier Expert

Life used to be so simple.

5th Mar 2015 05:45 UTCDon Saathoff Expert

Rock, it still is if you ignore the rabble-rousers and can still laugh.....

5th Mar 2015 14:42 UTCWayne Corwin

L:-DL

5th Mar 2015 16:07 UTCElise Skalwold

Alfredo – I'm fascinated by this. If Gilson synthetic turquoise contains “turquoise” as well as other components as reported in literature, I wonder what the “turquoise” is (the Gilson product's properties meet enough criteria in order to be considered a synthetic). In the absence of any other clues, lapidary specimens can be separated by microscopic structure and confirmed with advanced instrumentation such as mid-infrared spectroscopy and X-ray diffraction patterns. I’m really curious about what the synthetic is being compared to in nature given newer ideas about what turquoise is mineralogically.

Alfredo Petrov Wrote:

> The first step in reaching an understanding or

> consensus is to admit differences in usage do

> exist, and that that is not necessarily a bad

> thing or an "error".

Just to expand on that – in pursuit of mineralogy, along the way I've been surprised how much variation there is in the geological sciences regarding definitions and different understandings of some concepts depending on one's specialty. As for “gem people” – that’s really, really broad. Our friend Dick Hughes whom I've brought over to your Tucson booth (to his delight) published a great article co-authored with his mentor Dr. John L. Emmett entitled “Betwixt Two Worlds : A search for gemology in the 21st Century” archived here: http://www.ruby-sapphire.com/21st-century-gemology.htm Though I've never hesitated to argue with either of them over dinner, it may shed light for some on at least part of the “gem people” concept. My own direction goes down a path which is more narrowly defined; see a review of the first-ever Gemological Session of the GSA (2013) “Gemology bears triumphant tidings. A review of the historic 125th Anniversary Annual Meeting of the Geological Society of America” archived here: http://www.nordskip.com/GSA_Gemology_Session.pdf

Cheers!

Elise

5th Mar 2015 18:12 UTCOwen Melfyn Lewis

@David,

Many thanks for the link to the Minsocam paper, which was helpful to read and of which I have added a copy to my personal collection. For any interested, the chemical analysis by wt% of a sample from Greece makes an interesting read when put alongside the similar data from fifteen analyses of turquoise from three different localities in China shown here http://www.gemsdat.be/turquoise.htm (scroll right to the bottom of the page).

I was interested too in the determination of SG by the 'mixed liquid flotation' method. Having spent many days (running to weeks), years ago, trying to squeeze the last ounce out of that method, I finally gave it up for all but very specific needs. Learned a lot in the process though :-) I found the intractable problems to be:

- Difficulty in determining accurately the density of the final liquid mix at some fixed temperature.

- The need for strict temperature control of the liquid.

- The need for tables of temperature correction for each mix of liquids.

- The amount of time in preparation required to obtain as a one-off the SG of some unknown crystal.

That said, the value the authors derived is nicely within the uncomfortably loose range of SG values for turquoise that gemmologists have to content themselves with (see the above linked page for this also).

@ Alfredo, Reiner,

Re. moving the 'unwashed' photos to a Turquoise Group gallery: sounds like a plan to me that might help clear thought though, I suspect, that even this could not remove all dubiety from the winnowed turquoise species gallery. A most thought-provoking paper in my little collection is a doctoral thesis on how emerald may be identified and whether a given sample can be be tied to its locality of origin with reasonable certainty. For the purposes of this discussion, there were two of the conclusions that bear pondering on:

- Detection by wt% of a given element (Cr in the case of the paper) can vary by a greater margin between different specimens even from the same mine then may be the margin of variation between specimens from widely separated localities.

- That (given the laboratory resources of the materials science faculty of a major university) it is possible to identify the source locality of a mineral where there are extensive records for the same mineral from that locality. However, it requires an matrix of analytical methods, no single analysis being sufficient for this purpose,

I'll try and dig out and post a link to Dr Huong's paper as other may find it as thought-provoking as do I.

5th Mar 2015 23:21 UTCThomas Lühr Expert

Hello,

I can't understand your commotion and agree with Alfredo: it's a question of terminology.

Please correct me if i did not understand the point and let me give an other example, without gemmological reference:

The mineral 'wolframite' is known and called so since generations of miners. However it is not a mineral (in mineralogical sense) but a name for each member of the ferberite-hübnerite-series.

The mineralogist calls it (per definition) as ferberite if it contains more Fe than Mn, in opposite case hübnerite. If he means one of the the end members, he should add a word like "pure". Only a not analyzed specimen is called wolframite by the mineralogist.

However, for the miner is the exact composition not of interest (but the physical properties and the content of W) and the historical name wolframite is for him a "good" name, doesn't care about ferberite or hübnerite.

Now you can replace:

miner by gemmologist

wolframite by turquoise

hübnerite by planerite

ferberite by turquoise too !!

The last line may be cause the confusion: In this case one of the end members has the same name like the historical name of the mixtures.

In consequence the gemmologist calls all mixtures (depending of physical properties) as turquoise (analogue wolframite), the mineralogist (depending of composition) only 50% (analogue ferberite). The rest has to be called planerite.

Thomas

6th Mar 2015 01:22 UTCReiner Mielke Expert

The point is that this is a mineralogical database and not a gemstone database and I ( we) need to be able to rely on it for mineralogically correct data.

6th Mar 2015 01:39 UTCOwen Melfyn Lewis

John 18:38

6th Mar 2015 02:47 UTCJason Evans

Damn you guys, now I just had to get myself some turquoise crystals from Bishop mine, Lynch station.

6th Mar 2015 03:59 UTCAlfredo Petrov Manager

Part of the confusion would be eliminated if all mineral group names were like garnet, tourmaline, mica, amphibole, pyroxene, wolframite, etc.... ie. they did not duplicate a mineral species name! When groups like turquoise and jarosite are named after species, confusion is then guaranteed.

I will buy a whip as a gift for the organization entrusted with preventing confusion in mineral nomenclature, and ask them to please use it liberally on any subcommittee that yet again proposes a group name that duplicates a species name. :-D

6th Mar 2015 04:49 UTCD Mike Reinke

Jason,

You got some, that quickly?!

There will be 3 small shows around me this month. I can only hope the dealers aren't reading this, or know where I live, or I'll never be able afford some now! lol

Great verse, Owen. May I supplement it with 2 Tim. 2:14, it isn't good to fight over words, it overturns people. even mineral people, and they are a devoted bunch!

You have to be devoted, to wade into these waters of mixed definitions. Ours is not a lightweight hobby, I found out very quickly...

Mike

6th Mar 2015 13:25 UTCOwen Melfyn Lewis

D Mike Reinke Wrote:

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

> Great verse, Owen. May I supplement it with 2

> Tim. 2:14...

Aahh Mike, you certainly may...

Well, if nought else, this meandering thread has stimulated me to buy a facsimile copy of Joseph Pogue's work of 1915, 'The turquoise : a study of its history, mineralogy, geology, ethnology, archaeology, mythology, folkore, and technology' which, I understand, is still regarded as the bench-mark comprehensive study of the subject in the English language.

I agree with Alfredo (and Steve G, I think) that there can be no good end served by using the same word to name both a mineral species and the mineral group of which that species is a member. That said, it is not immediately clear to me which - the group or the species - should in every case keep the historic name. For example, in the case of 'turquoise', it seems to me that all interests would be best served by renaming the species and leaving the historic name to describe the group. But, taking the Beryl group/species, my feeling is that the reverse would be true and that the common good would be better served by reserving the historic name for the species and renaming the mineral group. What do others think?

6th Mar 2015 13:53 UTCAlfredo Petrov Manager

...it is not immediately clear to me which - the group or the species - should in every case keep the historic name. For example, in the case of 'turquoise', it seems to me that all interests would be best served by renaming the species and leaving the historic name to describe the group. But, taking the Beryl group/species, my feeling is that the reverse would be true and that the common good would be better served by reserving the historic name for the species and renaming the mineral group.

In this case I agree with Owen entirely. Unfortunately these decisions on reorganization of Groups are made by small subcommittees composed of a handful of mineralogists specializing in that group, with no mechanism that I'm aware of for any comments by the public (ie. anyone outside mineralogical academia, including gemmologists, curators...) until after the decisions are published, which is of course too late for anyone to say "Perhaps this group ought to have a different name?".

6th Mar 2015 14:21 UTCElise Skalwold

With a mixture of visitors to the museum, ranging from the academic community to the general public and all ages, all with different levels of interest and backgrounds, it is quite a task to meet all needs and to do so accurately (as well as to upgrade 150 years of labeling – I push for keeping and displaying all labels, even if the styles and concepts clash ). When they see a mineral specimen which is a “classic” gem material, familiar even from youth, such as tourmaline or garnet, the majority of visitors will be intrigued and usually recount some memory of it -- in a completely different mood which is absent when viewing [ insert your favorite ugly specimen]. Garnets and tourmalines are labeled (if known) almandine, spessartine, grossular, dravite, elbaite etc. But, a chunk of massive “turquoise” inevitably has been labeled simply "turquoise" with a chemical formula which may or may not have been determined with any analysis in the distant past. My interest in the discussion is that I am considering if and how to add informational labeling when there is only a very limited amount of space to do so. I look to MinDat and Fliecher’s for guidance, so the above type of discussion is very interesting to follow, especially in the case of turquoise which visitors associate (usually fondly) with an affordable, common gem -- and with a "ah-ha, so that's what it looks like!" as with other gem minerals. I'm still curious what the research gemologists who are nearly all mineralogists or chemists by training used to compare the Gilson synthetic to in nature, but that is an aside which perhaps I should not have brought up earlier. I did not mean to sway the discussion away from a purely mineralogical one and I look forward to further insights from the Mindat community.

6th Mar 2015 16:28 UTCOwen Melfyn Lewis

Elise,

This thread originated as a gentle discussion of turquoise jewellery, treatments and imitants, so your Gilson enquiry is really not out of place. O'Donoghue (after Webster) reports that the Gilson method might be a tweak on the Hofman method published in 1927 However his description of the Hofman method is too vague to serve as more than a pointer. MO'D points to 'Synthetic analogs and imitations of natural precious stones', a monograph available in Russian only, as a source of information on the Gilson method. Gilson worked with Russian colleagues on the method.

My understanding is that the Gilson business and its excellent products closed over 20 years ago and that he sold much/most of his know-how to Kyocera, Japan. That business, mainly through its ceramics division, continues experimental work on a range of synthetic gems and holds several Japanese patents. According to the CIBJO white book (2013) as at that date there was no synthetic turquoise in the market. I'm inclined to take that with a pinch of salt, it seeming more likely that it is there but rare as hen's teeth in comparison to the truckloads of imitant material and treated mined turquoise. It seems possible that a small amount of synthetic turquoise may be in circulation and passes cursory examination, when cut and polished, as being geologically formed.

8th Mar 2015 03:11 UTCRock Currier Expert

Ill kick in some money to be sure that they get a quality whip.

8th Mar 2015 03:25 UTCTony Albini

To add to the discussion, the late Dr. Gene Foord tested samples of "turquoise" from many localities and concluded that some of the material was turquoise, some turquoise and planerite, and some just Planerite. The Lynch Station, VA microcrystals had the highest mount of copper and were turquoise. There seemed to be a correlation between the deepness of the blue color, copper content and the material being turquoise. You can try to google his article, I cannot place my hands on my copy right now.

Tony Albini

8th Mar 2015 10:56 UTCDavid Von Bargen Manager

http://www.minersoc.org/pages/Archive-MM/Volume_62/62-1-93.pdf

8th Mar 2015 15:46 UTCOwen Melfyn Lewis

David Von Bargen Wrote:

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

> http://www.minersoc.org/pages/Archive-MM/Volume_62

> /62-1-93.pdf

Another for the archive. Many thanks, David.

8th Mar 2015 16:39 UTCChris Krietsch

[attachment 57547 IMG_0130c.jpg

Some Lynch Station Virginia material that I have had for over 35 years. Sorry for the photography, free hand with a cannon camera. These are in my collection unmarked, I guess I should put a label on them so when I am gone someone will know what it is.

9th Mar 2015 17:14 UTCChris Krietsch

13th Mar 2015 00:33 UTCJason Evans

Here is my little specimen which arrived today!

10th May 2015 19:07 UTCJosé Zendrera 🌟 Manager

Recently I noticed a significant difference in UV response between two supposed turquoise in my collection.

Piece at right was bought personally in 1972 in Mashhad, Iran, which is close to Nishâpûr deposit so I would say that it has many probabilities to be real turquoise. Accurately measured density is 2.49 (little low for turquoise, probably due to embedded matrix), hardness is about 5 and streak is light-bluish white. Size is 5 x 4 x 1 cm

Specimen at left was bought in Kathmandu, Nepal, in 2012, allegedly coming from Iran across China following the Silk Road. Density is 2.66 and hardness also about 5, both can be hardly scratched with a knife. Don't looks dyed, I sanded 2 mm deep for checking and found no changes. Powder (= streak) is also light-bluish white. Size: 6 x 4 x 3 cm

Until here, no much difference between them aside from color hue and inter-nodular matrix. But fluorescence is very different. I know that many "turquoise" are in fact other species (howilite, planerite, other turquoise group minerals or even magnesite, aragonite and others) but I don't know the UV response of these minerals (except aragonite, which use to be fluorescent but not in these colors).

Maybe someone can give a clue...

1 - Halogen light

2 - Long wave UV (385 nm, filtered)

3 - Short wave UV (250 nm, filtered) (overexposed pic)

11th May 2015 03:02 UTCAlfredo Petrov Manager

No way to tell for sure from the photo, but my guess is that the FL response from the specimen on the left is due to synthetic organic binders/stabilizers. The reddish fluorescence under SW UV in the specimen on the right is probably from the rock matrix (partially kaolinized feldspars, for example). Given a choice, I'd want the piece on the right ;-)

11th May 2015 20:57 UTCJosé Zendrera 🌟 Manager

Thanks Alfredo, feldspar is a good candidate for dull reddish fluorescence.

I did another fluorescence comparative, this time with all available turquoise at home, including cabochons and even pendants and a ring. Except the big nodule at left, all pieces were bought long ago in Mashhad, not far from the most classic turquoise deposit ( http://www.mindat.org/loc-25357.html ).

Note that under long wave (at center) cabochons at left fluoresce in same color than the big nodule. Also they have similar black embedded material. Green stuff, so-called "green turquoise" in origin, should be a mix of different minerals absolutely inert under UV.

Under short wave (below) the fluorescence of big nodule is still suspiciously strong and uniform. Draws attention the green small fluorescences in small pieces at right, which correspond to clear stuff that scratches glass, then should be quartz. No idea of what could be the yellow shine on the ring.

26th Jun 2016 11:11 UTCAbdullah Paracha

hello

I just bought this ring and was confused whether this is original turquoise or not so, i put a lighter against the stone which turned the stone blackish it did not melt and did not smell although there was a cracking type of sound and very small bubbles appeared on the stone which I cleared by the tissue the surface of the stone is kind of rough can anyone please tell me what type of turquoise is this and whether this is original or not please do reply

26th Jun 2016 12:37 UTCBob Harman

Sorry but I can't tell much from your photos. CHEERS.......BOB

26th Jun 2016 16:43 UTCJosé Zendrera 🌟 Manager

Hello Abdullah,

It looks like the teardrop piece above at right in my last photo. Maybe a sub-product of the turquoise mines, not exactly turquoise but a mix of secondary copper and mafic minerals.

I personally bought this pendant time ago in a workshop in Mashad (Iran), near the turquoise mines so that I have no doubts about his authenticy.

The small bubbles that appeared when it was burned could be a varnish used to give polished appearance but I can not confirm this because I did not subjected my piece to so destructive burning test, you were very bold.

Cheers.

27th Jun 2016 04:00 UTCDoug Daniels

Hard to tell. The color is certainly nothing like the turquoise I've seen (blues to greens) - that one is dark green and black. Hopefully not from your lighter testing (which was not a good idea). The reaction you did see could be a result of a resin used to stabilize whatever it is that the stone is.

27th Jun 2016 04:52 UTCWayne Corwin

It could also be a blue colored varnish that they used to give it a polished appearance :-(

12th Aug 2016 15:15 UTCMirva L

I bought this stone donut awhile ago from a gemstone shop in Finland. It was labelled turquoise, and when asked the shop assistant confirmed it was indeed turquoise. However, being naturally suspicious, I'd like some second opinions. Especially because the brown in the drill hole worries me. The size is about 4,5cm/1.77in and it cost around 20€/$22.

- Mirva

13th Aug 2016 03:11 UTCDoug Daniels

I too am suspicious of the color in the hole. Looking at a blow-up of the photo, that area seems (on my monitor) to be a mottled black or dark brown with an darkish olive green. And there seems to be a thin rind of the blue material along the back of the hole. Then again, on the front, some of the thin dark brown cracks/veinlets/whatever you want to call them, do appear to extend into the material in the hole. So, to me, very hard to say for sure one way or another. Was anything in the hole when you obtained the object?

13th Aug 2016 09:28 UTCMirva L

No, there was nothing in the hole. On their website they sell these as pendants with leather cords through the hole, but at the shop they were sold loose. I took a couple more pictures from other angles. On the other face it has an area that is sort of whitish-brown. I've read that turquoise can sometimes have spots like that, but it also makes me wonder if this is dyed Howlite or something similar.

- Mirva

15th Sep 2016 22:00 UTCOowho

WhatEVER it is, it sure is purty!

16th Sep 2016 00:06 UTCOwen Melfyn Lewis

Sad to say, I don't think we can tell for sure by looking at this piece (at least, I can't) but I am suspicious. If one has the tools and the knowledge there are a series of basic tests that, taken together should tell you if it is not turquoise. These are:

- Spectroscope. Not all turquoise specimen will show a clear spectrum but those for those that do the absorption spectrum is diagnostic.Cut -off in the yellow as about 570nm and all longer wavelengths absorbed is diagnostic if present. Also look for an absorption line in the violet at about 430nm and maybe also at 420 nm - or else there may be a cut-off absorption of all wavelengths above anout 425nm. . A very powerful incandescent light source is needed.

- Refractive index (using spot method). 1.61

- Mohs hardness. 5-6.

- SG. 2.76 +0.34/-0.14.

If you can find a rock and gem club anywhere near you they should be happy to help you by trying these doing these tests for you.

Best guess off the photos? For me, it'd be reconstructed turquoise waste. That would figure at the price too.But certain proof of that would require destructive testing :-/

Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 25, 2024 15:43:32

Go to top of page