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Mineralogical Classificationquestionable minerals
16th Dec 2005 05:10 UTCJosiah (Joe) Heyman
Just curious to see which ones people suggest.
Joe
16th Dec 2005 09:52 UTCMarco E. Ciriotti Manager
impossible to list all questionable minerals species. In my database they are 180.
Ciao.
Marco
16th Dec 2005 13:11 UTCJim Ferraiolo
As Peter responded (to your duplicate post), deinerite is one. Horsfordite is another, though a new paper is coming out on horsfordite. Gengenbachite is a recently published mineral/name not approved by the IMA.
Clark's "Hey's Mineral Index, 3th Edition" (1993), Bayliss's "Glossary of Obsolete Mineral Names" (2000) and DeFourestier's "Glossary of Mineral Synonyms" (1999) are excellent starting places.
16th Dec 2005 14:31 UTCMarco E. Ciriotti Manager
Referenza:
• Bellezza, M. (2005): Crystal-chemical study of Zr,Ti,Nb,REE-disilicates with general formula M16(Si2O7)4(O,OH,F)8, belonging to the cuspidine, gotzenite-rosenbuschite-seidozerite and rinkite families. Plinius, 31, 51-54.
Here are the new proposed formulae:
Mosandrite: (Na,Ca)3(Ca,Ce)4(Ti,Nb,Al,Zr)(Si2O7)2(OH,F,O)4·1.4H2O
Rinkite: (Na,Ca)3(Ca,Ce)4(Ti,Nb)(Si2O7)2(O,F)4
17th Dec 2005 04:10 UTCJosiah (Joe) Heyman
Joe
17th Dec 2005 05:03 UTCAlan Plante
That said, there are also a few post-IMA inception "species" that also need to be looked at again with the proverbial fine-tooth-SEM & XRD to see if they still merit being approved species or not...
Alan
17th Dec 2005 10:56 UTCDavid Von Bargen Manager
From IMA website
"The Commission on New Minerals and Mineral Names (CNMMN) of the International Mineralogical Association (IMA) was established in 1959 for the purpose of controlling the introduction of new minerals and mineral names, and of rationalising mineral nomenclature."
17th Dec 2005 21:26 UTCAlan Plante
The point is that at the time the IMA began approving new species any and all "previously accepted species" (by whoever...) prior to that were accepted *by default* as valid, since the IMA did nothing to accept or discredit any of those "previously accepted species."
I didn't intend to make it seem as though the IMA waved some magic wand over some specific list and said "Presto! - These are valid species." They didn't. They simply allowed all previously accepted species to continue as accepted species until such time as someone discredited them.
(We seem to get into this debate over how "old species" were "grandfathered" every time the question of pre-IMA speices comes up... Maybe we need to come up with a statement that we all agree is accurate and unambiguous and use only that statement when the topic comes up! :~} )
KOR!
Alan
28th Dec 2005 06:48 UTCJosiah (Joe) Heyman
I've compiled an interesting list of minerals listed as questionable/doubtful (thus meriting the statement, "probably not a mineral") on Mindat, using the search function, but which are listed as minerals in the 2004 Fleischer's Glossary. This suggest a number of questions as to what minerals are or are not debatable, and (more interestingly) why in particular cases are they up for debate?
I have included comments but omitted question marks by composition or crystal system. Fleischer's = (F.)
They are in the apparently random sequence produced by the search engine-sorry.
Joe
Pitticite
Thorogummite
Carbonate-fluorapatite
Hydroscarbroite
Heliophyllite (F. says "needs further study")
Ferrisymplesite
Joséite-B
Uhligite
Basaluminite
Redingtonite
Nasledovite
Zaratite
Ilmenorutile
Ferrotantalite
Herderite (F: "a doubtful species")
Calcurmolite
Przhevalskite
Kurumsakite
Delvauxite
Shubnikovite
Ilsemannite (F: "needs much further study")
Jordisite
Parajamesonite (F: "status doubtful")
Stetefeldtite
Coeruleolactite
Kamacite
Partzite
Beryllite
Yukonite
Cadwaladerite
Liskeardite
Natroniobite
Meta-uranopilite
Gerasimovskite
Montanite
Stevensite
Douglasite
Cebollite
Pseudocotunnite (F: "needs much further study")
Hectorite
Idaite (F: "inadequately defined")
Sakharovaite
Giorgiosite (F: "incompletely described")
Rauvite
Kolovratite (F: "requires further investigation")
Manganbelyankinite
Zirklerite
Uvanite
Karpinskite
Richellite (F: "a species of doubtful status")
Pintadoite
Wattevillite
Cousinite (F: "inadequately described species")
Falkmanite
Clinoungemachite
Molybdophyllite
Meta-alunogen
Hydrophilite (F: "= Antarcticite or Sinjarite?")
Spadaite
Ustarasite
Bursaite
Matraite
Vanoxite (F: "needs additional study")
Rilandite (F: "needs further study")
Rosièresite (F: "species status uncertain, requires much more study")
Zincaluminite
Belyankinite
Vernadite
Arsenosulvanite
Barbertonite
28th Dec 2005 10:49 UTCMarco E. Ciriotti Manager
here is your list alphabetical ordered:
Arsenosulvanite
Barbertonite
Basaluminite
Belyankinite
Beryllite
Bursaite
Cadwaladerite
Calcurmolite
Carbonate-fluorapatite
Cebollite
Clinoungemachite
Coeruleolactite
Cousinite (F: "inadequately described species")
Delvauxite
Douglasite
Falkmanite
Ferrisymplesite
Ferrotantalite
Gerasimovskite
Giorgiosite (F: "incompletely described")
Hectorite
Heliophyllite (F. says "needs further study")
Herderite (F: "a doubtful species")
Hydrophilite (F: "= Antarcticite or Sinjarite?")
Hydroscarbroite
Idaite (F: "inadequately defined")
Ilmenorutile
Ilsemannite (F: "needs much further study")
Jordisite
Joséite-B
Kamacite
Karpinskite
Kolovratite (F: "requires further investigation")
Kurumsakite
Liskeardite
Manganbelyankinite
Matraite
Meta-alunogen
Meta-uranopilite
Molybdophyllite
Montanite
Nasledovite
Natroniobite
Parajamesonite (F: "status doubtful")
Partzite
Pintadoite
Pitticite
Przhevalskite
Pseudocotunnite (F: "needs much further study")
Rauvite
Redingtonite
Richellite (F: "a species of doubtful status")
Rilandite (F: "needs further study")
Rosièresite (F: "species status uncertain, requires much more study")
Sakharovaite
Shubnikovite
Spadaite
Stetefeldtite
Stevensite
Thorogummite
Uhligite
Ustarasite
Uvanite
Vanoxite (F: "needs additional study")
Vernadite
Wattevillite
Yukonite
Zaratite
Zincaluminite
Zirklerite
They are surely the most "important" questionable mineral species, but some other can be added...
And here is the Q list (#179) from my DB (based on MINERAL MDI database), that you can compared with the previous:
Q Achtaragdite
Q Anhydrokainite
Q Argentite
Q Arkelite
Q Arseniodialyte
Q Arsenosulvanite
Q Arzrunite
Q Azovskite
Q Barbertonite
Q Basaluminite
Q Batavite
Q Baumhauerite-II
Q Beckelite-(Ce)
Q Beegerite
Q Bellite
Q Belmontite
Q Belyankinite
Q Beryllite
Q Birunite
Q Blakeite
Q Boldyrevite
Q Bolivarite
Q Bonchevite
Q Brongniartite
Q Bursaite
Q Cadwaladerite
Q Ca-huréaulite
Q Calciogadolinite
Q Calcioursilite
Q Calciovolborthite
Q Calcurmolite
Q Calcybeborosilite-(Y)
Q Carbonate-fluorapatite
Q Carbonate-hydroxylapatite
Q Cebollite
Q Cerfluorite
Q Chinglusuite
Q Chloromagnesite
Q Cirrolite
Q Clinoungemachite
Q Coeruleolactite
Q Cousinite
Q Cuproadamite
Q Cuproauride
Q Cuproscheelite
Q Delvauxite
Q Dienerite
Q Douglasite
Q Duftite-beta
Q Dunhamite
Q Egueiite
Q Evansite
Q Falkmanite
Q Ferrisymplesite
Q Ferrotantalite
Q Ferrotellurite
Q Foshallasite
Q Gerasimovskite
Q Giannettite
Q Giorgiosite
Q Glaserite
Q Grovesite
Q Hectorite -16Ã…
Q Heliophyllite
Q Herderite
Q Hochschildite
Q Horobetsuite
Q Horsfordite
Q Hyalophane
Q Hyalosiderite
Q Hydrocassiterite
Q Hydrophilite
Q Hydroromeite
Q Hydroscarbroite
Q Idaite
Q Ilmenorutile
Q Ilsemannite
Q Iodine
Q Isoclasite
Q Istisuite
Q Jaipurite
Q Jeromite
Q Jordisite
Q Joséite-B
Q Jusite
Q Kamacite
Q Karpinskite
Q Kerolite
Q Kerstenite
Q Kitaibelite
Q Kliachite
Q Koivinite-(Y)
Q Kolovratite
Q Kurumsakite
Q Lechatelierite
Q Lessingite-(Ce)
Q Leucoxene
Q Lewisite
Q Liskeardite
Q Manganbelyankinite
Q Mátraite
Q Maufite
Q Meta-alunogen
Q Meta-natrium-uranospinite
Q Meta-uramphite
Q Meta-uranopilite
Q Molybdophyllite-27Ã…
Q Monimolite
Q Montanite
Q Nasledovite
Q Natroniobite
Q Nickellinnaeite
Q Nitrammite
Q Orthobrochantite
Q Palladinite
Q Paragearksutite
Q Parajamesonite
Q Partzite
Q Percylite
Q Phosphate-walpurgite
Q Picroilmenite
Q Pigotite
Q Pimelite
Q Pintadoite
Q PÃsekite-(Y)
Q Pitticite
Q Planoferrite
Q Plumosite
Q Priazovite
Q Przhevalskite
Q Pseudoboehmite
Q Pseudocotunnite
Q Ramdohrite
Q Ranquilite
Q Rathite II
Q Rathite III
Q Rauvite
Q Redingtonite
Q Renardite
Q Richellite
Q Rilandite
Q Rosiérésite
Q Sakharovaite
Q Sanderite
Q Severginite
Q Shubnikovite
Q Smirnovskite
Q Spadaite
Q Stetefeldtite
Q Stevensite-15Ã…
Q Strüverite
Q Sturtite
Q Tagilite
Q Tertschite
Q Thorogummite
Q Titanclinohumite
Q Titanium
Q Titanomaghemite
Q Tocornalite
Q Tsilaisite
Q Uhligite
Q Ustarasite
Q Uvanite
Q Vanoxite
Q Varlamoffite
Q Vernadite
Q Volkovite
Q Wattevillite
Q Winebergite
Q Yttrofluorite
Q Yukonite
Q Zaratite
Q Zinalsite
Q Zincaluminite
Q Zincblödite
Q Zinc-fauserite
Q Zinclavendulan
Q Zincrosasite
Q Zirklerite
... some other names can be added (e.g. amber and troilite that are - at today - classified as G in MINERAL MDI, etc.).
Some of them can be recognized as valid or - at the contrary - discredited after general revision and structure determination.
28th Dec 2005 17:10 UTCJosiah (Joe) Heyman
Joe
29th Dec 2005 18:46 UTCAlfredo Petrov Manager
Within these lists, we can distinguish different types of 'questionability':
1) Minerals wrongly described, so that they actually correspond to some previously accepted species.
2) Minerals which do exist as described, but should have been classified as varieties of another species by current rules (ilmenorutile, hibschite, etc.).
3) Minerals which are so inadequately described that we do not have enough information to make a decision about whether they are species or not (horsfordite, etc.); some may well be real species, others not.
4) Substances adequately described, but which are not mineral species because there is no evidence that they occur naturally (eg: diaoyudaoite).
The IMA's discreditation procedure was designed mainly with case 1 in mind, and sometimes case 3, and it doesn't really operate in cases 2 & 4. In case 2, the problem is one of semantics and definitions, not of whether the species was properly described or not. In case 3, discreditation can only be done if there is some material to work on; if no material is available (dienerite, jeromite), the discreditation procedure can't be carried out and the nonexistent 'mineral' remains on some lists forever, which seems rather silly. In case 4, restudy of the original type material is not necessarily going to produce results different from the original study, and it is impossible to prove a negative (ie. that a substance does NOT occur in Nature).
Cheers,
Alfredo
30th Dec 2005 16:55 UTCjohan
i am always amazed with peoples analytical abilities, i.e. breaking down the available data into a few factual sentences. however, in this case you missed one alfredo:
5. species that do exist and are quite valid as species (type material or not) but for some reason in history have been q-marked.
(i do not know wether ima have votings on such q-marked species in order to have them taken away from the q-list, either by re-approving the status or finally discredit them - maybe someone else could answer this - but for sure it is not done on a routine basis)
Anyhow my knowledge is unfortunately not encyclopedic and i can only give an example of which i am sure - ferrotantalite - and that fellow Nb-Ta-oxide experts will confirm. (the story here is generalized just out of my head to get to the point, i can dig up some references for anyone interested)
Historically the columbite-tantalite group was divided into four species depending on the Mn-Fe and Nb-Ta dominance of the two cation-sites in the structure: manganotantalite, tantalite (later ferrotantalite), columbite (later ferrocolumbite) and manganotantalite. There existed also a tetragonal dimorph to tantalite, tapiolite.
One rainy day someone decided to x-ray a lot of columbite-group minerals and found that most "tantalites" are tetragonal and thus tapiolites (later to become ferrotapiolites), it is probably after this that the q-mark appeared. however, later on there are several works that report co-existence of ferrotantalite-ferrotapiolite pairs, confirmed with xrd- and emp-data. Generally speaking one can differentiate ferrotapiolites from ferrotantalites by chemistry; ferrotapiolites are extremely Ta- and mostly Fe-dominant whereas ferrotantalites are much more intermediate in composition but still with Ta>Nb and Fe>Mn. If one plot the data there is a clear mixing gap between the two species.
I am sure that there are more examples of this 5th category on the q-list, but of course with other stories that placed them there.
all best
johan
30th Dec 2005 17:44 UTCAlan Plante
I think the CNMMN welcomes proposals for the validation of "Q" species when the proposers have the proof positive that is needed to remove the "Q". The folks who spent a rainy day with the X-ray equipment should have submitted their data to the CNMMN in the form of a validation proposal. Then the "Q" would have been removed from in front of the name.
But the CNMMN can't take action until someone presents them with the porposal. How would they know someone spent a rainy day proving that the "Q" doesn't belong if the committee isn't presented with the evidence?
The researchers may have validated the species, but they failed to tell the world - so the "Q" remains. How sad...
Regards
Alan
30th Dec 2005 21:40 UTCjohan
you misunderstood, the "rainy day part" concerns my speculation on how the q actually got there. The work i am "referring" to was most probably published as it evidently led to a Q in front of the ferrotantalite. Is it certain that the Q followed after a formal proposal? If it did - fine - but I am not so sure...
Anyhow, the "later on" part "refers" to documentation done in the same spirit (good old columbite group empiricism).
I know for sure that some researchers grind on forever on their different lifetime projects. In this perspective a q-list is very hard to keep track on. Formal proposals by such researchers is not the number one priority. They just go "it seems that all ferrotantalites actually have tapiolite structures..." then they grind on for another couple of years and document co-existence of ferrotantalite-ferrotapiolite and say "hmm, after all ferrotantalites DO exist after all..."
It seems strange to me that a q in front of for example the ilmenorutile remains, because it is no longer a question wether it is a species of its own as Alfredo pointed out - it is a niobian rutile, something that people researching it has pointed out in articles long time ago. Why cant cmnmnmnm take action by themselves? They got their list as a starter, they got all the proofs in the articles, it's just to grind on...
all best
johan
31st Dec 2005 02:58 UTCJim Ferraiolo
The mineralogical literature and nomenclature prior to the IMA-CNMMN is the history of the science, and while not considered completely 'untouchable' by the Commission, nothing should be changed without validating research work, not by a proclamation of the Commission. If it comes up during sub-committee work for redefining the nomenclature of a mineral group, then the reason for the nomenclature changes must be validated as well.
The 'Q' mineral list was not given by the IMA, but by MDI-Mineral in their database, and, though Ernie Nickel is a former chair of the IMA-CNMMN, it is not an 'official' listing.
Checking Bayliss or Defourestier or Clark will give a large list of questionable, poorly defined, misidentified, etc. mineral names. And not always the same ones.
I look at mineral literature, nomenclature, and classification a great deal, and have had to decide whether a mineral/ mineral name is valid, or not, based on the literature. It's been a preoccupation for 30+ years.
For example, I would consider bellite a discredited mineral (= chromium-bearing phosphatian silicatian mimetite) , but Marco has it on his Q list, and MDI-Mineral lists it as Q,with the comment'Probably a chromium-bearing mimetite'. And I've recently seen dealers selling new specimens of 'bellite'. Doesn't hurt it as a specimen, and doesn't hurt to label it 'bellite'. Good shorthand.
Happy New Year!
31st Dec 2005 10:16 UTCErnst A.J. Burke
It is good to see that so many persons discuss the status of the minerals and the mineral names described before 1959, the starting year of the IMA-CNMMN. The assignment of the status for these minerals is indeed a personal matter, as it is not always clear how one should decide on their validity or not.
The CNMMN has a list (see the CNMMN website) of its about 4000 decisions since 1959: this list is called the ARD list (Approved, Redefined, Discredited).
The minerals from before 1959 are called G (grandfathered) or Q (questionable) in the MDI database of Nickel and Nicol. This database has moreover the status N (Non-approved) for minerals published after 1959 without approval of the CNMMN.
The CNMMN is aware of the different status of many G and Q minerals by different authors. The CNMMN has therefore decided to do something about these three categories of minerals (= the GQN list).
During 2005, the CNMMN members and a number of other persons have been asked to comment the status of the about 1600 minerals on this GQN list provided by Ernie Nickel (taken out of the MDI database). This has resulted in thousands of remarks, which now have to be compared to each other. The intended result is a corrected list of GQN minerals, to be discussed in 2006.
It is clear that there will never be an unanimous opinion on the status of these 1600 minerals, how does one decide on G or Q for minerals described in the past without having access to the original material, and especially without the time or means to re-investigate all 1600 minerals. The resulting CNMMN list of GQN minerals will thus always be a provisional list, changes will happen all the time with the progress in science. But the inconsistencies will have been taken out of the list, we hope.
So, please be patient for the time being. When this GQN list will be published, we expect of course many additional remarks, also from the readers and users of this forum. They will be very welcome, but not now, there is plenty of work as it is!
3rd Jan 2006 15:34 UTCAlfredo Petrov Manager
Cheers,
Alfredo
3rd Jan 2006 15:41 UTCJim Ferraiolo
3rd Jan 2006 15:58 UTCMarco E. Ciriotti Manager
3rd Jan 2006 17:23 UTCAlan Plante
The current definition does make allowance for amorphous materials - pretty much saying what you suggest, that if it can be fully and uniquivocally defined chemically, it can be given approval. The actual wording in the IMA paper defining a mineral (Nickel, E.H., 1995, The definition of a mineral. Published simultaneously in several journals, e.g., Can. Min. 33, 689-690) reads:
"The term 'crystallinity', as generally used in mineralogy, means atomic ordering on a scale that can produce an 'indexable' (i.e. with Miller indicies) diffraction pattern when the substance is traversed by a wave with a suitable wavelength (X-ray, electrons, neutrons, etc.) However, some naturally occuring substances are noncrystalline. Such substances can be divided into two catagories: 1) amorphous, substances that have never been crystalline and do not reflect X rays or electrons, and 2) metamict, those that were crystalline at one time, but whose crystallinity has been destroyed by ionizing radiation. Some mineralogists are reluctant to accept amorphous substances as minerals because of the difficulty in determining whether the substance is a true chemical compound or a mixture, and the impossibility of characterizing it completely; some prefer to call such substances 'mineraloids'. However, some amorphous substances (e.g., georgeite, calciouranoite) have been accepted as minerals by the CNMMN.
"With modern techniques, it is possible to study amorphous phases more effectively than was possible in the past. Spectroscopic methods associated with complete chemical analysis commonly can identify an amorphous phase unequivocally. In fact, appropriate spectroscopies (e.g., IR, NMR, Raman, EXAFS, Mossbauer) can reveal the three-dimensional short-range structural environment of each element (chemical bonds). Of course, without the possibility of obtaining a complete crystal-structure analysis, which can give coordinates and nature of the atoms, the necessity of a complete chemical analysis is more stingent with amorphous material than with a crystalline phase.
"The basis for accepting a naturally occurring amorphous phase as a mineral could be: (1) a series of complete quantitative chemical analyses that are sufficient to reveal the chemical composition of all the grains in the specimen, (2) physiochemical (normally spectroscopic) data that prove the uniqueness of the phase, and (3) evidence that the material cannot produce an 'indexable' diffraction pattern, both in the natural state, and after treatment by some phsiochemical solid-state process (e.g., heating).
"Metamict substances, if formed by geologic processes, are accepted as minerals if it can be established with reasonable certainty that the original substance (before metamictization) was a crystalline mineral of the same bulk composition. Evidence for this includes the restoration of crystallinity by appropriate heat-treatment and the compatability of the diffraction pattern of the heat-treated product with the external morphology (if any) of the original crystal (e.g., fergusonite-(Y))."
I kind of like that. - To me it is a rational approach to dealing with the fact that Nature is messy. The commission is basically saying that it will approve an amorphous or metamict mineral if the proposer can prove it isn't a mixture. And it is clear from the paper that this proof is possible - it can be done to a reasonable certainty. So things like opal and georgeite don't get swept under the rug just because they don't fit our notion of "The Rules."
Anyway, I think what Ernie Nickel wrote makes it pretty clear that just because a mineral is amorphous or metamict doesn't mean it's status as a mineral is suspect. In each case, it behooves the suspicous worker to prove *their* case! :~}
KOR!
Alan
4th Jan 2006 10:08 UTCErnst A.J. Burke
4th Jan 2006 10:51 UTCMarco E. Ciriotti Manager
Ferrisymplesite can deserve, instead, the status of valid species.
IMA CNMMN, at today, approved or redefined only the following eight non crystalline mineral species:
calciouranoite
georgeite
meymacite
rowlandite-(Y)
santabarbaraite
thorosteenstrupine
umbozerite
yttrobetafite-(Y)
all the others are grandafathered (6 in my database) or questionable (18 in my DB, including ferrisymplesite) species.
31st Jan 2006 02:37 UTCRalph S Bottrill 🌟 Manager
Ralph
31st Jan 2006 10:07 UTCMarco E. Ciriotti Manager
31st Jan 2006 23:15 UTCRalph S Bottrill 🌟 Manager
I found there is a co-type specumen in existence (Belgium: ULG-Liège) so hopefully someone will check it out.
Ralph
1st Feb 2006 01:49 UTCJim Ferraiolo
Hey 3rd edition lists hydrocassiterite = syn. of varlamoffite.
Strunz 3rd edition (1957) = synonym of souxite <=varlamoffite>
deForestier lists it as = 'impure Cassiterite '
Bayliss lists it as = 'Fe-(OH)-rich cassiterite, Chudoba,
54(1971)'
Bayliss also lists hydro-kassiterit = 'Fe-(OH)-rich cassiterite, Lapis 21(1),49(1996)'
1st Feb 2006 10:42 UTCMarco E. Ciriotti Manager
3rd Feb 2006 02:06 UTCRalph S Bottrill 🌟 Manager
You seem to have a great library!
It seems ~50:50 (or maybe 40:60) whether you put hydrocassiterite in with varlamoffite or cassiterite; there again I have some doubts about whether varlamoffite is just an impure cassiterite too.
Ralph
6th Feb 2006 19:31 UTCjimferraiolo
Thanks. I keep a few volumes around. Probably varlamoffite is the same as souxite, and both are hydroxyl-bearing cassiterite. I'll poke around a bit, and see if I can come up with anything else.
7th Feb 2006 01:54 UTCjimferraiolo
Of interest, though:
A 1993 paper in Mineral. Zhurnal 15(4), 94-101 was abstracted in An.Min. 80,850(1995). Varlamoffite from various deposits were studied using a variety of methods, including radiography, analytical elctron microscopy, Mossbauer, infrared, X-ray electron microscopy, thermal analysis, and phase chemical analysis. Varlamoffite from the Tigrinoye deposit has an average comp. of Sn2FeO5(OH). The discussion by the abstractor states that 'The results seem to validate a previously ill-defined species and should be submittedto the CNMMN for a formal redefinition of the mineral'.
A 1985 Chinese paper concerning the weathered belts in the albitized granite in Guangxi. It mentions that varlamoffite may result from weathering of stannite or tin-bearing minerals, and hypergene cassiterite resulted from further oxidation and dehydration of varlamoffite. One of the sections of Gunter Moh's 1977 NJMA paper 'Ore minerals' discusses Ge-content of wood tin and varlamoffite, and a series of weathering experiments of stannite resulting in 'hydrocassiterite'. There's more, if you're interested.
A 1982 Acta Petrologica Min. et Analytica (Chinese) 1(3) paper abstracted in Min.Abs<83M/3628> indicated the mineral is nearly amorphous, tetragonal at 1000oC, space group P42/mmm. A formula of (Sn0.48Fe0.28Al0.17Si0.11P0.05As0.01 2O3.
One not seen: "An example of well-developed varlamoffite", ZVMO 116, 454-458(1977).
Hope this helps (?)
7th Feb 2006 07:06 UTCRalph S Bottrill 🌟 Manager
Very useful, and this seems to agree with the Tasmanian "varlamoffite/hydrocassiterite" occurrences in weathered and retrograde skarns
Presumably the data was never submitted to the CNMMN.
regards
Ralph
7th Feb 2006 20:37 UTCjimferraiolo
Sorry about that.
12th Jul 2006 23:07 UTCDIEGO
Thank you
Diego
12th Jul 2006 23:31 UTCDavid Von Bargen Manager
13th Jul 2006 00:58 UTCPaul L. Boyer
13th Jul 2006 01:05 UTCJolyon Ralph Founder
The SS Cheerful was shipwrecked on 20 July 1885 and carried 28 and 56 pound ingots of cornish tin bearing the marks of the smelting houses of Treloweth - St Erth, Carnvedras - Truro, Trethellan - Truro, and Tamar - Bere Ferres. The wreck lies in 35 fathoms of water, 18 miles NNW of St Ives.
The 'abhurite' was formed by corrosion of these tin ingots in seawater. Consequently, it's not a valid mineral (at least in this instance) and would be better classed as an artifact. Even though the corrosion and formation of the material was a natural process, because it started from a man-made source material, it disqualifies itself from being a true mineral.
Jolyon
20th Jul 2006 22:27 UTCNora Graf
Nora Graf
Jerome State Historic Park
21st Jul 2006 00:02 UTCDavid Von Bargen Manager
However the material was first described in 1928 and thus predates the formation of the governing body of the CNMMN of the IMA. When they formed in 1959, they decided not to look into the minerals that had already been described. Various authors have decided which minerals are true minerals and which don't deserve to be considered "true" minerals. This leaves a bit of wiggle room for some species which are not well characterised even today or where the type material has become lost. Some people consider jeromite to be a valid (but poorly defined mineral) while others don't think it deserves species status.
Currently, to be named a mineral species, the type material must be depositted in a museum. In the 1920's this was not a requirement and tracking down the type specimens can be a rather arduous undertaking. You would have to see what happened to the specimens of the author (and whether he traded material with museums or collectors or if he was affiliated with a university that keeps a mineral collection). From this period, quite a number of type specimen locations in collections are not known (and Jeromite belongs to this group).
I hope you weren't looking for a definitive answer.
25th Jul 2006 16:49 UTCNora Graf
Nora
25th Jul 2006 17:09 UTCAlan Plante
To add a bit to what David wrote, here's the current definition of a "mineral."
"In general terms, a mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geologic processes." (Nickel, 1995, The definition of a mineral, Canadian Mineralogist, 33, 689.)
The requirement that is "has been formed as a result of geologic processes" excludes quite a few materials that have resulted from human interactions - such as mine fires, smelter dross, etc. The requirement that "it is normally crystalline" is not hard and fast: eg., opal is considered to be a valid mineral species.
There are also a lot of materials that were considered valid mineral species prior to the advent of the IMA CNMMN - including a few that would not be given species status if they were proposed to the commission today. As these are re-visited by researchers they become discredited. But in the absence of modern study they remain "accepted" as species. Basically, the commission did not go through the old list and discredit anything. We consider all these pre-IMA species to be "grandfathered" - valid until proven otherwise.
If you can get hold of a copy of the Nickel paper you can read the entire thing - see what it has to say about exceptions to the rule, where the dividing line is placed in special cases. I think it - the paper - came out in the American Mineralogist around the same time. It was basically an IMA CNMMN update, widely published to reach as many mineralogists as possible.
Regards
Alan
25th Jul 2006 17:21 UTCDavid Von Bargen Manager
http://www.geo.vu.nl/users/ima-cnmmn/cnmmn98.pdf
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