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LocalitiesDeo Darrah, Kuran Wa Munjan District, Badakhshan, Afghanistan

22nd Apr 2015 22:56 UTCJosé Zendrera 🌟 Manager

After reading what is affirmed in this thread http://www.mindat.org/forum.php?read,9,351661,351757#msg-351757 regarding the undetectable caesium content of blue beryl from this locality, maybe the presence of vorobyevite in Deo Darrah must be revised to avoid confusion.

I open this talk page just in case somebody want add any additional data or comment on this matter before to remove this variety from Deo Darrah mineral list.

23rd Apr 2015 11:39 UTCDavid Von Bargen Manager

Even though the only reference is from a dealer source, it would probably be better to classify it as erroneously reported rather than simply deleting it.

23rd Apr 2015 14:50 UTCJosé Zendrera 🌟 Manager

Thanks David, as you said will be the best way to arrange this.

We still wait some days before change it.

23rd Apr 2015 18:24 UTCMark Heintzelman 🌟 Expert

Strike-out for vorobyevite added to locality.

MRH

23rd Apr 2015 18:35 UTCReiner Mielke Expert

Trouble is Lavinsky's photos are still misleading. I find it rather annoying that after spending 10's of thousands of dollars ( if not more) on obtaining the samples Lavinsky could not afford to spend $40 more to get them analyzed!? Boggles my mind.

23rd Apr 2015 21:24 UTCDavid Von Bargen Manager

ID's sort of depend on the source for the specimens. If a person claims that they are a particular mineral or says so and so IDed them, is it worth spending the time and money to confirm them. When you deal with thousands of specimens, sometimes things get past you. If something proves to be a bad ID, most reputable dealers will refund the purchase price to their customers.

23rd Apr 2015 22:25 UTCJolyon Ralph Founder

Don't be so hasty.

The descriptions from Lavinsky say the specimens were analysed by Dr Federico Pezzotta in Milan, so I have reached out to him to get some further information.

Jolyon

24th Apr 2015 01:22 UTCBob Harman

To me, one of the quintessential problems with today's hi end mineral collecting is the lack of any type of universally accepted certificate of analysis authenticity for rare minerals or "genuineness" of each hi end specimen. Universally accepted certificates for hi end mineral specimens should follow those that have been issued for many years when buying hi end stamps or coins. CHEERS……BOB

24th Apr 2015 15:00 UTCOwen Melfyn Lewis

From Sinkansas's excellent compendium of information in 'Emerald and Other Beryls', the following is a synopsis of research into alkalis in beryl by Feklichev, Beus and Deere, Howie and Zussman:

- Caesium. Most analyses show less than 4%. Feklichev found a maximum of 4.13% As a single exception, one blue beryl from Arizona had been found to contain 11.3% Cs₂O.

- Sodium. Very common. Most analyses 2% or less. Maximum of 4.22% Na₂O (Feklichev).

- Calcium. Common. Most analyses <1%. One report of 3.98% (Feklichev).

- Rubidium. Rare. Analyses give <0.02% but Beus reports a maximum of 1.35%.

- Lithium. Common. Most < 1%. Maximum of 1.39% (Feklichev).

- Magnesium. Common, Mostly 1.5% or less of MgO. Maximum of 3.37% (Feklichev).

- Potassium. Uncommon. Most <0.50% K₂O.

- Barium. Very rare. 0.15% to 0.21%.

- Strontium. Very rare. 0.01% to 0.06%

These figures are from research papers published in the 1960's. In several respects this work supplanted earlier studies from the early 20th C, Significantly, this work lowered the maximum alkali levels previously claimed to occur.

For her doctoral thesis in 2008, Le Thi Thu Huong made a comprehensive study of 260 beryls (emeralds) from 13 locations in Europe, Asia, Africa and South America. Her chemical analyses were made using LA-ICP-MS and EMPA at the University of Mainz. Between 1 and 5 specimens from each of these locations were analysed in this manner. Her reporting of alkali levels in these samples was as follows:

- Caesium. Up to 1338 ppm (= 0.139 wt %) 'Non-schist' types (Colombia and Nigeria) < 0.01 wt%.

- Sodium. 'Non-schist type' 0.096 - 0.924 wt%. 'Schist type' specimens contained 1.048 - 1.696 wt%.

- Calcium. Not reported.

- Rubidium. Values up to 0.0138 wt% in Madagascar. All other 0.0016 down to 0.0003 wt%.

- Lithium. Up to 0.174 wt%. 'Non-schist' samples contained the least. (0.007 - 0.025 wt%).

- Magnesium. Schist type 0.39 - 0.550 wt%. Non-schist 0.002 - 0.308 wt%.

- Potassium. Max 0.285 wt%. Min 0.0006wt%.

- Barium. Not reported.

- Strontium. Present in Austrian samples only to a max level of 0.0007 wt%

One has to be careful not to compare apples and oranges but it does seem that these recent results, obtained using the most modern methods of analysis, report levels of alkali occurrence in beryl at one or two orders of magnitude below the levels reported in the earlier studies. There is an implication here, I think, that the levels of Cs reported in the 20th C for vorobyevite and, much later, pezzottaite, should be usefully qualified by a note of the analytical processes by which the analyses were effected and validated. Is (e.g,) stoichoimetry any longer to be held as a sufficiently determinative analytical techique unless findings by such methods are validated/comparable with LA-ICP-MS and EMPA analyses?

In the case of the Deo Darrah 'vorobyevite' in particular, there seem to be the following open questions:

1. For the research reporting 'no Cs' found, what were the analytical methods and their standard of assurance in comparison to LA-ICP-MS and EMPA?

2. What (by wt%) was the level of Cs in beryl required to classify a specimen as vorobyevite and is presently required to classify as pezzottaite? It's a given that a related proportion of Li is also required for either (though that may not have been realised when vorobyevite was first analysed).

3. What analyses, by whom and using what method(s), have leading dealers relied on to sell the blue, tabular crystals from Deo Darrah as vorobyevite?

24th Apr 2015 17:55 UTCReiner Mielke Expert

The first set of analysis is as oxides the second not that is probably why the difference.

24th Apr 2015 21:51 UTCJolyon Ralph Founder

I heard back from Federico,. as we suspect the results also indicate that there is no Cs in the specimens, so the descriptions of the photos are incorrect.

He states:

- Concerning "blue rosterite" from Deo Darrah my first analyses revealed a very interesting composition at the rim of the crystals with rathe no Cs but locally an exceptional high content of alkalies such as Na and Ca. The interior of the crystals resulted quiet "normal" beryl, without any significant compositional anomaly (or at least this is what I found). Further studies, including a combined work on compositional and crystal-structural aspects are necessary to clarify the exact nature of such very unusual crystals. BW, I was supposing that the deep-blue color in Elba "blue rosterite" could be related to some Mn content with unusual valence for beryl, but indeed in the studied sample from Pakistan I found no Mn content but a tiny Fe content, enough to justify the blue color (similarly to aquamarine variety).

Now... the problem we have now is that according to mindat, these DO qualify as Vorobyevite because of their high alkali content. The description in the photos saying they are Cs-rich is wrong of course.

The next question is whether our definition of vorobyevite is wrong. We have rosterite as a synonym of vorobyevite.

Jolyon

24th Apr 2015 22:20 UTCMark Heintzelman 🌟 Expert

I don't believe in any way that the absence of Cs is acceptable for an I.D. of vovobyerite. Here is it's first publication in Dana's, where you will see that Cs is it's one and only primary descriptior.

The System of Mineralogy of James Dwight Dana, 1837-1868: Descriptive Mineralogy - completing the work to 1909. (the first Dana volume that Beryl var. Volbeyervite appears. Absent from the 6th edition, 1898 & it's 1899 appendix).

“Vorobeyevite” - W. J. Vernadsky [Trav. Mus. Geol. Ac. Sc. St. Pet., 2, 81, 1908], Zs. Kr., 50, 73, 1911. Name given to caesium beryl because of the description of such beryl from Lipowka, Ural Mts., by Vorobyev. Description of crystals and anal. of this beryl given. Discussion of chem. comp. of Beryl.

And the original description of Rosterite:

The System of Mineralogy of James Dwight Dana, 1837-1868: Descriptive Mineralogy - completing the work to 1898

Rosterite Grattarola. 1 c. A slightly altered variety of beryl from Elba, named after Dr. G. Roster. It occurs in short prismatic to tabular doubly-terminated crystals. In polarized light a basal section is divided into six sectors, corresponding to the prismatic edges, for the three alternate of which the extinction is the same. Optically biaxial. Color pale rose-red. Anal. 1-4, Grattarola; 1, 2, from the ends of a crystal, which had a nucleus of normal beryl (anal. 3); 4, “typical rosterite.”

There was no mention of any relationship between these two types of Beryls. According to contemporary records of the U.S. National museum (Smithsonian) their catalogue listings were as follows: Group 7: Cesium beryls (included Morganite, Goshenite and by 1911, also Voroberite). Roserite, Emerald and Aquamarine were listed separately. Rosterite was not catalogued as a variety of Cesium Beryl, let alone of Voroberite alone).

MRH

25th Apr 2015 00:22 UTCOwen Melfyn Lewis

@ Reiner,

> The first set of analysis is as oxides the second not that is probably why the difference.

Variance to between one and two orders of magnitude? Surely not?

@ Jolyon,

At the risk of stretching goodwill, it is possible to ascertain the method of analysis used and the levels of Na and/or Ca determined?

@ Mark,

I agree that no Cs == no vorobyevite. However, this still begs the question as to what level of Cs is required to make a vorobyevite call. Such evidence as I have been able to find in the literature (see previous post) indicated that not only is stoichoimetric detemination (that would have been used 150 years ago) much less sensitive than LA-ICP-MS and EMPA but the Cs levels obtained may be orders of magnitude greater than those obtained by modern methods of quantitative analysis.

"1. For the research reporting 'no Cs' found, what were the analytical methods and their standard of assurance in comparison to LA-ICP-MS and EMPA?

2. What (by wt%) was the level of Cs in beryl required to classify a specimen as vorobyevite and is presently required to classify as pezzottaite? It's a given that a related proportion of Li is also required for either (though than may not have been realised when vorobyevite was first analysed).

3. What analyses, by whom and using what method(s), have leading dealers relied on to sell the blue, tabular crystals from Deo Darrah as vorobyevite?"

I think these are fair questions, the answers to which might shed some light.

25th Apr 2015 01:10 UTCMark Heintzelman 🌟 Expert

Owen I do see the problem,

These definition were based on a measure which we now see were wholly unreliable. Question is, how do we now fit these old definitions into a modern scheme, based on more reliable lab result? The fit may simply not be there, it may be a matter of "re-invention" if we feel these old observed "varieties" must match what we can now know of them!!

I have failed to find any greater detail on any references/report noted by Dana for voroborite. Even so, as you note, the levels of Cs noted in that report were probably far form accurate.

What you say are all quite valid questions, if there is a need to marry the old with the new. This is a pretty good example of why I feel old varietal names like this ought to be largely disregarded, their use relegated to specimens from the original localities from which they were originally described for historical purposes only, not classification purposes.

At the end of the day as far as these Deo Darrah materials are concerned, it would require a whole lot of fudging and excuses to suggest the use of the term voroberite for them was justifiable.

MRH

25th Apr 2015 15:12 UTCOwen Melfyn Lewis

Mark Heintzelman Wrote:

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

> What you say are all quite valid questions, if

> there is a need to marry the old with the new.

> This is a pretty good example of why I feel old

> varietal names like this ought to be largely

> disregarded, their use relegated to specimens from

> the original localities from which they were

> originally described for historical purposes only,

> not classification purposes.

Yes, it seems that in determination of the composition of specimens of beryl (and many other grand-fathered minerals?) there are four generations of analytical methodology, each bringing with it greater certainty in its determinations:

- 18th/19th C stoichoimetry. Still in use right up to today.

- Early 20th C crystallography. Bragg (L)'s and West's bench-mark work, the definitive 'The Structure of Beryl', published in the Proceedings of the Royal Society in 1926,

- Second half of 20th C. Intensive study to determine the levels and effects of substitutional 'foreign' ion relacement in the perfect theoretical formulae and structures, , plus the interstitial entrapment of foreign ions in the unit crystal lattice. EMPA becomes widely available, with detection capability of a limited range of elements at an accuracy down to 100 ppm (0.01%).

- Beginning of the 21st C, laser ablation-inductively coupled plasma-mass spectrometry. This did not suddenly appear full-fledged but rather is the latest fruit of a 100-year chain of incremental developments. This development brings with it major improvements in both the completeness and accuracy of quantitative chemical analysis - but still will not give the answer to 'life, the universe and everything'.

It must follow that where more perfect modern methods show old species/varietal differentiations to be incorrect they should quietly be dropped or corrected (IMA of course only concerning itself with species).

In the case of Cs in beryl, Penfield (American Journal of Science, 1884) reported (stoichoimetric?) determination of Cs in two out of seven (random?) beryl specimens and Na as present in all. In 2008, from LA-ICP-MS and EMPA analyses of 36 specimens of beryl (var. emerald) from 13 globally distributed sites, Huong reported Cs as present in specimens from 10 out of the 13 sites. All specimens from Colombia, Nigeria and some from Madagascar were at levels too low for EMPA detection.

It seems to follow that continuance of the use of the varietal distinction 'vorobyevite' is unwarranted unless the level of Cs in beryl, as determined in the 19th C, as the basis of the varietal differentiation is known. If the detection of Cs at any level, unspecified, is sufficient to apply the 'vorobyevite' label, then the whole exercise is 'reductio ad absurdum' as there is evidence that most beryl carries in it some Cs

> At the end of the day as far as these Deo Darrah

> materials are concerned, it would require a whole

> lot of fudging and excuses to suggest the use of

> the term voroberite for them was justifiable.

I am grinding no axe here but, like most of us I think, search after truth and some modus vivendi that is (sufficiently) truthful. It seems to me that a flat 'No Cs found' does require the support of knowing the accuracy and limit of detectability inherent in the analytical method(s) used. It seems to me quite possible that the variety vorobyevite entered the nomenclature without any requisite measure of Cs being specified. If that is indeed so, then the use of the name really should be abandoned - equally for Russian material as for the blue stuff from Deo Darrah, it being counter-productive to accept as vorobyevite beryl with Cs at any detectable level.

As a separate issue, the Deo Darrah blue beryl, has been traded at vorobyevite at a price premium of x10 or more over non-gem specimens of beryl of similar specimen quality. I think that this should be pointed out to the dealers concerned with a request that they comment.

25th Apr 2015 17:45 UTCJolyon Ralph Founder

Various analysis saying no significant Cs detected means that it cannot possibly be "Cs-rich" beryl as was described.

I agree that the name should not be used for this material and I will revert it to 'beryl' on all samples from this locality.

Jolyon

27th Apr 2015 16:34 UTCMark Heintzelman 🌟 Expert

I have managed to find more complete reference for vorobyvite, an abstract from Neues Jahrbuch für Mineralogie 1909 vol II, pg 21-23. Unfortunately my grasp of the german language is insufficient for the task at hand. If someone could glean these pages for data/information to make the vorobyvite mineral page more complete, it would be much appreciated!

one of three:

27th Apr 2015 16:35 UTCMark Heintzelman 🌟 Expert

two of three:

27th Apr 2015 16:36 UTCMark Heintzelman 🌟 Expert

Three of three:

PS: According to:

A (Fifth) list of new Mineral names: with an index of authors.

by L.J.Spencer, M.A. F.G.S.

Assistant in the Mineral Department of the British Museum.

[Communicated June 7, 1910]

A similar name “wowbewite” was previously applied to tabular crystals of rose-coloured and colourless beryl, rich in alkalis, from Madagascar, or what we now know as a separate species, pezzottaite. This name was oft referenced along with Vorobyevite, however Dana opted to exclude this version of spelling, offering only an alternate "w" rather that "v".

27th Apr 2015 18:04 UTCOwen Melfyn Lewis

Mark,

This source suggests that:

1. That Cs in beryl can be a structural element as opposed to being a charge-balancing capture in the channel formed by the beryl triple cyclosilicate ring.

2. Some of the formulaic variations given do not seem to support the essential beryl cyclosilicate structure.

The page references Penfield's work (published 1884?) and therefore is later than that. Is it also prior to Bragg and West's definitive paper of 1926 that first set down essential structure of beryl? My understanding is that both Na and Cs atoms are now known to be too large to substitute for Be or Al in the beryl molecular structure but this is not true of some other alkali metals such as Rb, K or Li. Further, I know of no modern source that suggests the structural incorporation of H₂ into beryl (though there is often a channel entrapment of H₂O) .

So how does this early document help us at this point (other than to suggest that the initial differentiation of vorobyevite must have been on based on an inaccurate definition of the essential beryl formula and structure and therefore should be quietly buried and forgotten by all except scientific historians? It seems to me that a misconceived structure is at least as seriously misleading as a mistaken locality.

27th Apr 2015 18:11 UTCMark Heintzelman 🌟 Expert

Offering what I could find of a more original description, and with it a strong suggestion that the use of this term/name is an anathema to modern classification. Best left to histories "missteps", not to be revived for any purpose other than historic (of course, pending a modern examination of this material to see if note of any meaningful variation can be made to warrant this names usage).

MRH

27th Apr 2015 18:19 UTCOwen Melfyn Lewis

D'accord! :)-D

5th May 2015 06:32 UTCIan Nicastro

Hey gang, I just noticed this thread.

I wanted to alert you to the fact that my dealer friend in Peshawar just found out there is a new deposit for 'Vorobyevite' in Pakistan (Shigar and Nagar Valleys)... the crystals look a little different than the Deo Darrah material and the matrix looks a lot different (however these new pieces were being sold as from Deo Darrah because the dealers were mislead by their supplier). I had Raman done on these and the spectra for this 'Vorobyevite' looks different than that of common beryl, aquamarine, emerald and morganite that my friend at the Univ of Santa Cruz used as comparison references. He also noted that these crystals have water and gave Cr3+ luminescence. Again my friend and I have no access to microprobe, so we aren't sure if it's Na and K that's distorting the crystal structure. These new crystals have a very thin flat tabular band of blue beryl and then a highly etched elongated appearance for the top and bottoms. As I mentioned these were sold as coming from Deo Darrah (I've only seen these etched looking crystals for sale in the past few months). This new info about the Pakistan location resulted when we let our dealer friend know that the Raman spectra looked different than Aquamarine, and he informed his supplier who then disclosed the new location. I do not have the spectra on hand but I can get them from my friend if needed, but I find it pretty interesting that the beryl structure is distorted enough to show a difference by Raman.

http://www.edwardsminerals.com/proddetail.asp?prod=Afg020 this is what the new Pakistan material looks like. I have a couple off matrix, which is what we used for the Raman.

5th May 2015 17:18 UTCMark Heintzelman 🌟 Expert

Interesting maybe, but you seem to be missing the point of the conclusion made here:

There is currently NO legitimate use for a fuzzy term like "Vorobyevite" beyond a historical one, a "side-note" applied only to beryls from the original localities.

The name/term for now represents nothing more than a historical observation of an ill-defined cesium beryl, and is altogether meaningless even as a variety. Again. "pending an accurate/modern examination of the original material to see if note of any meaningful variation CAN actually be made to warrant it's usage".

Unless or until that is done, focusing on the character/qualities of these Pakistan beryls "of there own accord" would be the only reasonable & legitimate way to describe them.

MRH

5th May 2015 18:04 UTCRob Woodside 🌟 Manager

Thanks Ian, Mark is right, but you do have a new variety and the locality info is important.

Does anyone know what causes tabular versus prismatic Beryls?

5th May 2015 21:41 UTCIan Nicastro

MRH I follow your argument, I was just using ' ' around the name instead of typing: specimens-formerly-called-vorobyevite from Afghanistan/Pakistan. It just seems to me that these flattened Beryl from Afghanistan and Pakistan do seem to be a bit different in both chemistry and crystal structure and I wish that someone qualified to do so could take a more thorough look at these and publish their research. I realized in another thread I accidentally typed these were Na/K rich, but I double checked the letter I was given from Pezzotta's analysis and it's exactly what Jolyon quoted... Na/Ca rich along the edges of the crystals, so my apologies for typing that wrong before. I assume it is still scientifically correct to refer to these as Alkali-beryl in conversations, even though that's not a species or variety?

I do have to confess that I am having trouble understanding your sources of evidence in this thread I got lost with the old German references ... any chance you can boil down the results you found in like a couple sentences that I can pass on to the dealers about when and who messed up the definition historically?

I have access to these publications, which is all I could find on the subject of traditional 'Vorobyevite' in english:

-A single-crystal neutron and X-ray diffraction study of pezzottaite, Cs(Be2Li)Al2Si6O18

-Alkali Metals in Beryl and Their Role in the Formation of Derivative Structural Motifs: Comparative Crystal Chemistry of Vorobyevite and Pezzottaite.

I think it would make sense to link to this thread for the blurb about Vorobyevite not being listed on the Deo Darrah location page, instead of the thread you guys have linked currently, as this thread has a ton more info. Also thanks for everyone looking into this subject more.

5th May 2015 22:00 UTCRob Woodside 🌟 Manager

Added Thanks Ian.

6th May 2015 02:22 UTCTimothy Blackwood

Hi,

Earlier in this thread, I saw a reference to the specimens labeled vorobyevite on Rob Lavinsky's website. It was suggested that they hadn't been analyzed.

To clarify, here is the paragraph found at the top of the first page of specimens on Rob's site:

"Vorobyevite (Rosterite) - Unusual Beryls

July 13, 2014 - Vorobyevite (sometimes called Rosterite) is a rare variety of Beryl that does not qualify as its own species. The name was applied to both colourless cesium-bearing beryls from the Urals and rose-coloured and colourless alkali-rich beryls from Madagascar, all of which showed sharp hexagonal crystals which are shortened on the c-axis. This new find had a similar morphology, which led to puzzlement over what it was. Although the morphology of these crystals is clearly unusual (see photos), and although the crystal habit of these strange beryls is similar to Pezzotaite (which is a valid species of beryl), these do not contain enough cesium to be classified a new species under current mineralogical rules. To be sure of the classification of this unusual material, when the pocket was found, we sent the whole lot to the lab of Dr. Federico Pezzotta in Milan. He performed analyses on multiple specimens to show that one can consider these to be cesium-rich, and he believes this is the reason for the crystal habit we see here (bowed-in centers; sandwich-like look on the edge faces with color zoning; and unusual sharply tabular morphology). I was able to buy nearly the entire pocket of this material, which I was told was mined in mid-2012 in the summer season. The altitude is a problem - it is difficult to access and the mining season here is only 3 months. No more were found in 2014 to date, despite an attempt. While we were initially told the specimens were from Gilgit, we now have better confirmation that the locality is Deo Darrah, Khash & Kuran Wa Munjan District, Badakhshan Prov., Afghanistan."

To emphasize: "To be sure of the classification of this unusual material, when the pocket was found, we sent the whole lot to the lab of Dr. Federico Pezzotta in Milan. He performed analyses on multiple specimens to show that one can consider these to be cesium-rich, and he believes this is the reason for the crystal habit we see here (bowed-in centers; sandwich-like look on the edge faces with color zoning; and unusual sharply tabular morphology)."

If you have any questions, it would be best to ask Rob. He may have a copy of the analyses.

Best wishes,

Tim Blackwood

Cohasset, Minnesota, USA

6th May 2015 02:30 UTCIan Nicastro

Hey Tim, I have a copy of the letter Dr. Pezzotta sent to Rob, and Jolyon also copied a message from Dr. Pezotta as well... and in both documents Dr. Pezzotta clearly states he found no Cesium in these crystals and that there was notable levels of Na and Ca in the periphery of the crystals.

It's important to preface this that at the time the first discovery of these were made in Afghanistan in 2012, the location was first listed as Pakistan... and later changed to Deo Darrah, Afghanistan...

"Dear Rob,

finally I found some time to give you the right infos concerning the flat-beryl crystals from "Pakistan".

- tabular beryl crystals, colorless to pale pink, have been first described from Elba island pegmatites in the second half of the 19th century. At the time, it was already recognized they were containing anomalous quantities of alkalies, including Cs. This unusual variety of beryl (which was including several anomalies in density and optical properties) was named "rosterite" honoring renewed university professor, photography pioneer, and mineral collector Giorgio Roster from Florence.

- Among rarities in Elba pegmatites, a further variety of beryl forming strongly tabular crystals of deep blue color, up to a few millimeters in diameter, was described in some samples in association with multicolored tourmalines. This very rare variety was named "blue rosterite". No analytical data were available about these crystals due to their rarity. Some years ago, I was able to find a nice specimen of "blue rosterite" in a locality described at the end of the 19th century. As prof. Carlo Aurisicchio of the CNR of Rome was performing since many years a study on Elba beryls, I gave the sample to him. For various reasons (probably Carlo was afraid to damage the specimen for analyzing) at the end the specimen returned back without being studied and data about such beryl variety were never published.

- In the meantime, pezzottaite was discovered in Madagascar and vorobyevite was named as a new mineral (but not IMA approved) by some russian mineralogists.

- It was very exciting for me when I knew that a group of "blue rosterite" crystals was found in "Pakistan" last year (I still do not know exactly the locality) in association with polychrome tourmaline in a paragenesis very simile to Elba. For this reason I arranged to buy all the material (or rather all) from the discovery and I selected a few specimens for analysis.

- To be honest, I am convinced that at least one new mineral specie if not two or even three, of the beryl group, are present in "rosterite", "vorobyevite", and "blue rosterite" from various localities in the world (including Afghanistan, Pakistan, Elba, Burma, Russia, Madagascar), nevertheless the lack of a systematic and complete sampling in the hands of the right researchers prevented, till now, such studies.

- Concerning "blue rosterite" from "Pakistan" my first analyses revealed a very interesting composition at the rim of the crystals with rather no Cs but locally an exceptional high content of alkalies such as Na and Ca. The interior of the crystals resulted quiet "normal" beryl, without any significant compositional anomaly (or at least this is what I found). Further studies, including a combined work on compositional and crystal-structural aspects are necessary to clarify the exact nature of such very unusual crystals. BW, I was supposing that the deep-blue color in Elba "blue rosterite" could be related to some Mn content with unusual valence for beryl, but indeed in the studied sample from Pakistan I found no Mn content but a tiny Fe content, enough to justify the blue color (similarly to aquamarine variety)."

13th Sep 2016 00:20 UTCIan Nicastro

I know this discussion has been inactive for awhile, but I recently had thorough analysis performed on a specimen I own of tabular Aquamarine from Deo Darrah, Afghanistan that was obtained from a friend in Peshawar in 2015, that was sold as 'Vorobyevite,' and the results are interesting and actually corroborate with the information Rob Lavinsky listed during his sale of 'Vorobyevite' specimens from the 2012 find... in other words they do have Cesium... but they also have notable Sodium levels.

The analysis was performed at a research lab in the United States. The lab also tested a specimen of Afghan 'Vorobyevite' for another collector a few weeks before they tested my sample and saw similar results. I had also heard much earlier this past year that the Larson Family sent a specimen of Afghan tabular Aqua that was sold to them as 'Vorobyevite' to a lab in France for thorough testing and also received word that it had notable Cesium levels.

First a qualitative analysis was done on my specimen by EDXRF that showed Cesium was present.

ICPMS was then performed as a quantitative analysis at 12 different locations across the crystal. My specimen was one of those where the center of the tabular crystals was slightly yellowish and the rest of the crystal was blue. A couple of the crystals on my specimen are partly broken, so it provided a nice cross section across the width of the crystal. A broken crystal face was used for the analysis. None of the sampling seemed to show a notable correlation for higher concentrations at the edges versus the center of the crystal.

The results were:

-Fe ranged from 2.6k-6.9k ppm/w (mean=4.2k). This Fe is assumed to be 3+.

-Na levels ranged from 2.7k-4.1k ppm/w (mean=3.2k).

-Cs levels ranged from 821-1.1k ppm/w (mean=941).

-Ca levels ranged from 350-923 ppm/w (mean=548).

-K levels were low.

Other elements that were not brought up in previous discussions:

-As levels ranged from 314-2.2k (mean=1.5k)

-Mg levels ranged from 177-1k ppm/w (mean=563).

-Li levels ranged from 250-400 ppm/w (mean=277), I didn't think anything of these low levels, but when the data was shown to a different researcher than the one who performed the testing, he told me to mention it here as Lithium substitution can do strange things to Beryl.

Additionally some quick testing was performed on the botryoidal drusy like crystals that were on the rest of the matrix. The resulting spectra obtained was not great, but reasonably matched that of tourmaline group minerals. I do recall hearing previously someone mentioned they had also IDed this material as Tourmaline group.

13th Sep 2016 12:10 UTCOwen Melfyn Lewis

Hi Ian,

Thanks for the interesting data. Here is a repeat of the quantative data (LA-ICP-MS and EMPA) reported in Le Huong's study of over a hundred samples of the emerald variety of beryl.

- Caesium. Up to 1338 ppm (= 0.139 wt %) 'Non-schist' types (Colombia and Nigeria) < 0.01 wt%.

- Sodium. 'Non-schist type' 0.096 - 0.924 wt%. 'Schist type' specimens contained 1.048 - 1.696 wt%.

- Calcium. Not reported.

- Rubidium. Values up to 0.0138 wt% in Madagascar. All other 0.0016 down to 0.0003 wt%.

- Lithium. Up to 0.174 wt%. 'Non-schist' samples contained the least. (0.007 - 0.025 wt%).

- Magnesium. Schist type 0.39 - 0.550 wt%. Non-schist 0.002 - 0.308 wt%.

- Potassium. Max 0.285 wt%. Min 0.0006wt%.

- Barium. Not reported.

- Strontium. Present in Austrian samples only to a max level of 0.0007 wt%

Added now:

- Iron. 0.002 - 0.893 wt%

- Sodium. 0.096 - 1.696 wt%

- Magnesium. 0.002 - 0.550 wt%

Ian Nicastro Wrote:

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

> ICPMS was then performed as a quantitative

> analysis at 12 different locations across the

> crystal.

>

> The results were:

> -Fe ranged from 2.6k-6.9k ppm/w (mean=4.2k). This

> Fe is assumed to be 3+.

> -Na levels ranged from 2.7k-4.1k ppm/w

> (mean=3.2k).

> -Cs levels ranged from 821-1.1k ppm/w (mean=941).

> -Ca levels ranged from 350-923 ppm/w (mean=548).

> -K levels were low.

>

> Other elements that were not brought up in

> previous discussions:

> -As levels ranged from 314-2.2k (mean=1.5k)

> -Mg levels ranged from 177-1k ppm/w (mean=563).

> -Li levels ranged from 250-400 ppm/w (mean=277), I

> didn't think anything of these low levels, but

> when the data was shown to a different researcher

> than the one who performed the testing, he told me

> to mention it here as Lithium substitution can do

> strange things to Beryl.

The points of interest are, I think:

- The level of Cs you report in your crystal is within the range reported for beryl var. emerald (schist type).

- Level of Li is higher than any expected to be found in emerald.

- Ca is not reported as present in any emerald.

- Na levels in your crystal are much higher.

These points may be significant to this whole debate. Enough to encourage more high-grade analyses of the Deo Darrah crystals? This first 'straw in the wind' seems to suggest that:

- The presence of Cs at the level you report is unlikely to bear significantly on the morphology of the Deo Darrah and other similarly formed beryl crystals.

- That the levels of Li, Na and Ca you report may bear significantly on the same.

13th Sep 2016 15:13 UTCRob Woodside 🌟 Manager

Ian, thanks for your efforts and a very interesting report.

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