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Where in the UK could I find out a country of origin for a gem/mineral specimen?
Posted by Nick Gilly
Nick Gilly May 22, 2018 06:18PMHi all.
As above, are there any services that do a non-destructive analysis of a mineral/gem specimen to determine the country of origin? If so, what sort of prices would they charge?
I have bought a specimen which I believe was misidentified, and if it is what I think it is, would be very interested to know the location it was likely found, as the info given is clearly wrong. I don't really want to post any more details until the sample is safe in my hands, but if all goes smoothly I will be able to provide more useful information then.
Sorry to be a bit cryptic but if I know I can send it to be analysed it would be very useful.
Owen Lewis May 22, 2018 09:28PMNick,
There are many labs that offer various types of quantitative analysis services. Unfortunately , none of these, fine though they indeed are can give you what you seek, I think. I say no more here since you don't want to discuss the piece at the moment. But you have mail ;-)
Doug Daniels May 23, 2018 04:39AMAs far as quantitative, non-destructive tests to determine even a country of origin, I'd say you're out of luck. You would need destructive tests (things like isotope ratios, matrix chemistry, and such). And even if you did those tests, you still couldn't guarantee even a country of origin. Your best bet, if you have an inkling as to what the specimen is, and maybe its locality, is to peruse the photos on Mindat of that mineral (or even other sites). And that method can only give a best guess, if any at all. If you can post a photo or two of it, maybe someone here will recognize it. Maybe.
Edited 1 time(s). Last edit at 05/23/2018 04:40AM by Doug Daniels.
Nick Gilly May 23, 2018 06:14AMThanks guys. It looks most like specimens from a particular country, comparing to pictures not just on Mindat, but elsewhere. However, assuming my suspicions are correct, there is one very important property that will be most easily determined once I have the specimen here.
Hopefully when the specimen arrives more pics and useful information will be enough to nail down a locality with reasonable certainty.
Owen Lewis May 23, 2018 12:47PMAbout 10 years ago, a Vietnamese lady was awarded her PhD from Mainz university for a most detailed study (including LA-ICP-MS) of emeralds from mines around the world. This excellent piece of work led to some significant and new conclusions. One of these is that, on occasion, it is possible to establish a greater variation in the chemical composition of emerald samples from different adits in the same mine than there is between emeralds from mines separated by thousands of miles. It would be irrational to think that this finding would hold true for beryl var. emerald alone; rather, it is to be expected that:
- Such a finding is made possible by improvements in the accuracy of results obtainable from mass spectrometry in recent years, an advantage simply not available when the most mineral compositions were last formally accepted (end of 19th and first half of the 20th C).
- That such a finding cannot be expected to be confined to emerald alone but , rather, will hold true across many/most/all minerals.
Or, in sum, reliance on quantitative mineral analyses to conclude a locality of origin with certainty is likely a thought past its sell by date. Dr Le Huong's conclusion was that, by using a battery of overlapping testing methods, absolute verification of a specimen's locality of origin may one day be possible but that it is not possible for the present. To which one might add the thought that even when possible could it ever be cost effective?
Nick Gilly May 23, 2018 02:43PMOK. I'll post one of the pics. It was sold as epidote from Långban in Sweden and apparently catalogued in 1934, but I'm sure you'll agree, the ID is incorrect:
It also has a really old $8.00 label on it, so the date might be right.
I just hope it wasn't listed with the wrong pics!
Nick Gilly May 23, 2018 05:47PMBTW the description says "There is an $8 price tag on the bag from Wards in 1934, though the original label has since been lost." (I think 'bag' is a typo for 'back'). Here's a pic showing the label:
From some Googling, Wards would appear to be "Ward's Natural Science Establishment". Seems they had a collection of various mineral specimens for academic use.
Peter Slootweg May 23, 2018 07:16PMWell Nick, it seems to me you have a lucky find here. No epidote for sure but a nice chrysoberyl var. alexandrite specimen. Check for colorchange under different lighting. By the looks of it i could very well be Russian. The biotite matix suits it perfectly and the lines on the pyramid faces should be twinning boundaries. A hardness test could tell more, it should scratch quartz.
Nick Gilly May 23, 2018 07:30PMHi Peter. This is what I was wondering. I'll be able to test for any colour change once the specimen arrives. The pics seem to all be taken using the same light source so it's difficult to assess, although some of the pics show purple-tinged areas, perhaps due to colour-change or a different light source interacting? There are some pics of Russian bluish-green chrysoberyl on Mindat with no apparent colour change, so it could be similar to them. Hence the need to have the specimen with me.
If it does turn out to be Russian alexandrite then yes it would be a very nice find.
Edited 1 time(s). Last edit at 05/25/2018 11:10PM by Nick Gilly.
Owen Lewis May 24, 2018 03:36AMJason,
Almost but its just a little trickier.
Single and reasonably clean crystals of chrysoberyl are usually strongly trichroic. Such gem quality chrysoberyl will show a colour change, the colours depending on the chromophore(s) present (pure chrysoberyl is colourless) and the axial line along which the crystal is viewed.
In addition to this strong pleochrism, where the chromophore in chrysoberyl is Cr3+, strength of the ligand field is about 2.17eV., lying between the 2.23eV at which the Cr gives ruby its wonderful red and the 2.05eV ligand field strength that the same Cr causes otherwise colourless beryl to appear emerald green. This is a rarely found balancing act. When this balance is present, a shift in the crystal's absorbtive/transmissive characteristics is sufficient to switch the perceived colour of the crystal from green (in blue/UV light) to red where the illumination is by a 'warm' incandescent light, especially candle light.
Simply put, 'colour' is just the human psycho-neural means of differentiating, communicating and storing in human memory small changes in the energy level in small parts of the already small spectrum of electro-magnetic radiation to which our eyes are sensitive and by which means we 'see'. 'Alexandrite effect' colour change in top quality alexandrite is almost startlingly vivid, where a small and subtle change in lighting causes a seemingly incongrously large change in colour.
The name 'alexandrite' should only be applied to chrysoberyl specimens showing the red to green colour change described here. The colours do not have to be strong or attractive but some colour change in chrysoberyl caused by a change in the colour temperature of the lighting source must be demonstrable. There is no other defining characteristic for alexandrite. Good SG and hardness observations taken together should be sufficiently definitive for all chrysoberyl.
Edited 1 time(s). Last edit at 05/24/2018 12:18PM by Owen Lewis.
Doug Daniels May 24, 2018 03:49AMRemember, the original question was, is there a non-destructive method to determine the locality of a specimen. At best, things like Raman spectroscopy and/or reflective light spectroscopy (both non-destructive) could give a likely ID of the specimen. However, they are not sensitive enough to give a locality, other than Earth. Again, there are destructive methods that can give some info, but there's not a big enough database of such detailed analyses that one could select a likely location. Wishful thinking for all of us, but if at all, far in the future.
Nick Gilly May 29, 2018 04:26PMDamn the suspense is killing me.
The specimen arrived at Heathrow last Friday but there has been no change in status since then, so it looks like it's stuck in customs limbo. As I paid $260 for this specimen I will be liable to import duty & VAT, which is probably going to mean this could take a while. I hope the customs men are gentle with it!
Can anyone offer any advice on anything I could do to speed this up?
Edited 1 time(s). Last edit at 05/29/2018 09:33PM by Nick Gilly.
Owen Lewis May 29, 2018 06:52PMNick,
It goes something like this:
- There is a handover ar LHR from UPS (etc.) to Royal Mail that appoints itself as *your* tax agent.
- The item is usually transferred to a special depot near Coventry.
- Once booked in there, Royal Mail informs you by post (snail mail) that it is holding the item pending collection of sums due, being (1) Royal Mail's fee for acting as your tax agent and (2) VAT due.
- You pay RM the total sum demanded which you can do via internet.
- On receipt of payment in full, RM will at once forward the item to you and pay to HMRC the tax due from you.
Depending on the US carrier, the collections arrangement in the UK may vary but is always via a 'tax agent'. There is nothing you can do to change or expedite the arrangement. Should you not pay up promptly, the item is returned to sender. You should see the tax demand on your doormat in the next couple of days. If you pay on the day of receipt, the item should be with you not more than two days after payment is made.
If you enter your tracking number into the Royal Mail tracking system, if they have it, the current state of processing can be read off there.
Best of luck!
Edited 1 time(s). Last edit at 05/29/2018 09:31PM by Owen Lewis.
Nick Gilly May 29, 2018 07:03PMThanks Owen.
Royal Mail haven't picked up the item in their system yet hence the likelihood that it is stuck in customs limbo. From what I have read the Royal Mail don't see items until they have been released by customs.
If any letter arrives I'll pay it ASAP.
Nick Gilly June 10, 2018 08:51PMAt last an update from the Royal Mail website:
"Your item has left our International Logistics Centre and is on its way to you. More information will be available as it travels through the network."
Does this mean it has finally left Customs? I hope so!
Edited 1 time(s). Last edit at 06/10/2018 08:51PM by Nick Gilly.
Nick Gilly June 12, 2018 04:40PMThe saga continues...
A couple of updates this morning, including one to say that the item had arrived at Basingstoke sorting office at 7.23 am. Then another at 9.45 am saying the item was being held pending a customs payment. Then another one at 12.49 pm informing me that there was an attempted delivery but no-one appeared to be in (my wife was home but asleep).
I get home and there is no 'Something For You' card, nothing. So I'm now on hold with Post Office customer services waiting to speak to someone to find out whether it can be redelivered, whether I have to pay the customs duty first, or what...
Edited 1 time(s). Last edit at 06/12/2018 04:41PM by Nick Gilly.
Nick Gilly June 15, 2018 04:48PMYay! The specimen arrived today!
It is gorgeous. The colour is way more saturated, greener and more vivid than on the pics above, a deep, emerald-like green with just a hint of blue. This is enhanced by some gemmy portions on some of the crystals. There appears to be a fairly complete trilling (as can be seen on the last pic) as well as intergrown twins and a few untwinned small crystals. One larger crystal has rough faces, maybe due to contacting, as the opposite side has sharp lustrous faces. The back side with the label shows the typical mica schist matrix.
I've tried it under an incandescent light source, and it looks very different: a much more drab purplish-greyish colour. The gemmy bits show purplish gleams. So there is a definite colour change going on.
For comparison, my much smaller Russian alexandrite specimen goes garnet red in some parts under incandescent light, but the green colour is much less attractive: a very dark forest green, almost blackish in some areas.
So, it would appear to be chrysoberyl, var. alexandrite.
The question is, where's it from?
Edited 2 time(s). Last edit at 06/20/2018 06:02PM by Nick Gilly.
Nick Gilly June 15, 2018 04:58PMInteresting. I told the seller that I thought it may be chrysoberyl and he says it is definitely from Långban in Sweden because it apparently shipped with a sahlinite specimen from there. The eBay pics shows all the documentation from Wards, dated 1934.
Weird. Chrysoberyl like that is not found anywhere in Sweden as far as I know. Maybe I should contact Wards and see if they know more about the specimen.
Nick Gilly June 15, 2018 07:29PMThanks Owen.
Actually the green does show through a bit under a tungsten bulb, but it's a dark, drab, greyish green. The gemmier bits do show a purplish tone with transmitted light.
I've emailed Wards Scientific Establishment about this too with a link to the auction. Maybe they keep records of previous specimens in their archives.
The auction also now says "This listing was ended by the seller because there was an error in the listing", even though I bought it. Maybe because I suggested the chrysoberyl ID?
Nick Gilly June 16, 2018 01:16PMWhat is it with digital cameras and alexandrite? I was hoping to take some more photos of this specimen to capture the beautiful emerald green colour of the crystals as seen in daylight. However, they look very different through the screen on the camera: a kind of teal with a greyish cast. Fiddling with the settings does make some differences but nothing that looks like the true colour of the specimen. Maybe I need a better camera.
I'd love to find out more about the history of this specimen. I suspect there may have been some sort of mix up with the labels and/or info. Maybe the price sticker isn't even from Wards?
I do like a good mystery. Fingers crossed Wards get back to me. That would be a start.
Owen Lewis June 16, 2018 03:36PMCamera. Can't really offer much that's useful without knowing what you use and what your working practices are. As a general guide:
- Accuracy (and honesty) of colour rendition depends on a correct white balance setting. This can be tweaked, post-camera, using good software like Adobe PhotoShop. However, it's best to set the white balance properly in the camera's firmware and to hold to a minimum the amount of post-camera image tweaking that might be required.
- Where capturing an alexandrite effect colour change in some chrysoberyl, fluorite, garnet, diopside etc., things get a little more complicated as one is switching between two light sources and the camera's white balance needs to reset for each change in light source. Most camera manufacturers build in an automated white balance setting the 'goodness' of which varies (I find the implementation in the Canon EOS firmware to be good enough for most of my needs, used with care. However, if you are unhappy with the results you are getting, try using manual white balance settings for each of your light sources and/or doing a final tweak in PhotoShop, if required.
Yes, the description of your specimen seems strange indeed. Even from a casual glance at your first shots, it's hard to think that piece to be epidote. Since epidote is found at Langban and since there is no known alexandrite within a thousand miles or there, there must surely have been a mislabelling at some point. Simple human error? If (very likely) testing confirms the mineral species as chrysoberyl I think you are likely to have to accept that the source locality is unknown.
I can't find it at all unexpected that some specimens are mis-described at point of sale but it might be interesting to see, by straw poll here, what level of inaccuracy is generally found by Mindaters? Or do most Mindaters simply go by looks and the sellers' claims only? With a small personal collection of about 600 pieces, I have found about 1 - 2% to have come to me misidentified.
Nick Gilly June 16, 2018 03:58PMI'd guess Malyshevo based on the appearance Owen. The emerald green colour (in daylight) and gemmy portions would suggest this. Alexandrites from Zimbabwe seem to be darker green to virtually black, the same with a lot of specimens from Brazil. Tanzanian specimens are lighter, attractive colours, but again have a different, distinctive look about them that do not match my specimen.
I will be taking it to the next Kempton Park Rock, Gem & Bead show to see if anyone else could offer any other suggestions, unless I can find out more from Wards.
Knut Eldjarn June 16, 2018 08:53PMNick,
Interesting and nice specimen. Surely Chrysoberyl/Alexandrite from Malyshevo in Russia. There is no way the specimen could be from Långban. Just a shot in the dark.... Gustav Flink was a Swedish school teacher, Långban specialist and mineral dealer who also visited the Urals in Russia purchasing minerals. I know he provided many specimens to mineral dealers and museums in the early part of the last century. Maybe the specimen originated with Flink together with specimens from Långban and that may explain the mislabelling (??). (But I do not believe it would have been misidentified by Wards, Flink or other dealers at the time...).
Nick Gilly June 17, 2018 08:05AMThanks very much Knut. That does sound like a possible lead.
If it did arrive via Gustav Flink, that would make the specimen's discovery before 1934, as he died in 1931. I found a biography page on him in Swedish, but using Google Translate I found this bit:
"In 1889, Flink made the first of its eleven trips to the Ural for the collection of minerals. The last took place in 1916. During these, a large number of mineral substances were collected and purchased, of which several noble stuffers were sold to museums and institutions at home and abroad."
Original Swedish text:
"F företog 1889 den första av sina elva resor till Ural för insamling av mineral. Den sista skedde 1916. Under dessa insamlades och inköptes ett stort antal mineralstuffer, varav åtskilliga ädelstensstuffer, vilka sedan försåldes till museer och institutioner i in-och utlandet."
So if it was via Flink then that would date it to some time between 1889 and 1916. It's possible that Wards then acquired it in 1934.
All speculation of course, but it's a possibility.
Edited 1 time(s). Last edit at 06/17/2018 08:06AM by Nick Gilly.
Nick Gilly June 23, 2018 05:09PMI've emailed the geology department of the Natural History Museum in Stockholm with some background info and a couple of pics of the specimen, to see if there is any possibility that it arrived via Gustaf Flink.
It's worth a go, as I have had no luck with the other couple of emails I've sent.
Nick Gilly June 29, 2018 04:48PMI had a reply from the Curator of Mineralogy at the Stockholm Natural History museum today:
"Many thanks for your interesting and very detailed question. I can just say that you are probably very close to the true in your arguments. Unfortunately there is not so much left of Gustaf Flinks papers, except for letters in several archives around in Europe and some manuscripts in our archive here at the museum. My additional comments to your thoughts about Flink having got them on one of his Russian trips, is that he mostly bought specimens in Russia and collected very few himself. We have a couple of alexandrites which originates from Flinks small mineral company and he had several dealing contacts in the US like Foote, English and I think also later on the Wards. So your specimen may have been part of a larger lot of Långban things and also Russian specimens sent to the Wards and later on mixed up in their store stock during the years. Anyway it’s a nice specimen of a classic Russian Alexandrite."
Thanks very much to Knut Eldjarn for giving me the lead to Gustaf Flink. I wouldn't have known to go in that direction otherwise.
Nice to know that the specimen may date to the time of the Russian Tsars.
Nick Gilly July 07, 2018 10:15PMI found my jeweller's loupe recently (it had ended up in our loft) and looking at the alexandrite specimen under it I notice what looks like a very small (approx 2 mm) colourless transparent crystal perched on one of the alexandrite crystals. This is near a cavity filled with a transclucent whitish material. I wonder if this is a phenakite crystal? It's so small that I hadn't noticed it before I looked at it under the loupe.
Nick Gilly December 31, 2018 01:28PMBTW I recently managed to take a picture of this specimen that is the closest I can get to capturing the colour correctly:
This was taken using my wife's big daylight bulb as a light source and selecting the 'blue sky mode' on the camera. There's still too much of a teal element to the colour but I don't think I'm going to get any better than that. The true colour is a deep emerald green in daylight. Using firelight as illumination (as would have been done when this gemstone was originally discovered) the crystals do appear a garnet-like dark red, with purplish overtones in places.
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