Mindat Logo
bannerbannerbannerbanner
Welcome!

Kaersutite-series

Posted by Olav Revheim  
Kaersutite-series
May 19, 2011 12:32PM
    
First Draft




Click here to view Best Minerals K , and here for Best Minerals A to Z and here for Fast Navigation for finished Best Minerals articles.



Can you help make this a better article? What good localities have we missed? Can you supply pictures of better specimens than those we show here? Can you give us more and better information about the specimens from these localities? Can you supply better geological or historical information on these localities?

The kaersutite series minerals are minerals in the amphibole group, see Amphibole Group main article for an overview of the group. The series contains the following minerals:

Ferrokaersutite
NaCa2(Fe4Ti)(Si6Al2)O22(OH)O

Kaersutite
NaCa2(Mg4Ti)(Si6Al2)O22(OH)O

Ferrikaersutite
NaCa2(Mg3Fe3+Ti)(Al2Si6O22)O2

kaersutite, Qaersut, 8,0cm FOV © Riksmuseet Stockholm


The kaersutite series minerals are a mineral group typical for the upper mantle. It is common, even a major constituent of alkali-magmas under high pressures between 25-35 kbar. On surface it can be found as sub mm grains in alkaline volcanic rocks, such as basanites and mugearites, or in alkaline plutonic rocks. Under certain circumstances, titanian amphiboles can also be formed at lower pressures, and it seems as the presence of F- may increase the stability field of kaersutitic amphiboles even at close to atmospheric pressure.

Sometimes, the magma can fractionate and allow larger crystals to form. It is believed that this is a very slow process, taking maybe thousands of years under constant pressue and temperature to form a 1 cm crystal. The crystal then has to be transported to the surface to be frozen as a crystal (megacryst, porfyroblast) in a fine grained volcanic matrix. The long time it takes to form a large kaersutite-series mineral makes the large, well developed crystals from some of the Czech locations truly remarkable.

Kaersutite series minerals may also be fomed in volcanic dikes. This is the case for the type locality Qaersut and also some of the other localities listed in this article. In these cases, the kaersutite-series minerals grow rather rapidly, only 25 days is estimated for the up to 4 in. long crystals found near the Hoover Dam in the US. The mechanisms causing the growth of large kaersutite crystals in these dikes has been compared to how pegmatites are formed. The Qaersut occurance has sometimes been referred to as a "kaersutite-pegmatite".

The Kaersutite-series minerals are difficult to deal with, even for an amphibole group series. The chemistry, the kaersutite minerals differs from most other amphibole minerals in that one of the space groups in the C position occupied by Titanium, a 4+ cation. Kaersutite and ferrokaersutite are the only minerals ( except obertiite) in the amphibole group with a 4+ cation in the C position as a part of the chemical formula. To compensate for this added charge on the cation side, one of the two OH positions is occupied by an O2- anion, thus balancing the formula.

The difficulties with the kaersutite series of minerals is related to the Ti cation. Normally, the actual composition of kaersutite is not very near the ideal end member formula presented at the top of this page. As for all amphiboles, the actual composition tends to be intermediate between different amphibole mineral species. This is particularily true for the position ideally filled with Ti 4+ cations. In order to qualify as a kaersutite, this position must contain more than 50% Ti , or Ti > 0,5 afu ( atoms pr. formula unit).

For most of the locations where kaersutite is known, the Ti content varies randomly between 0,3 and 0,7 afu, or in other words, the actual mineral varies randomly between pargasite and kaersutite. There are no way to tell the difference without a quantitative chemical analysis for the individual crystal, Even within the same location, the same rock, or even within the same crystal, this variation takes place. This can be illustrated from a location near Montreal, Canada, where titanian pargasite crystals had a thin coating of kaersutite.

As a consequence of this, we have the situation that there are several locations that produce nice kaersutite crystals, but also equally nice titanian pargasites. These two minerals cannot be distinghished from each by other means than a quantitive chemical analysis of the individual crystal. Since kaersutite is the rarer mineral of the two, titanian pargasites are often mislabeled as being kaersutite.

I have struggled on how to deal with this in this article. For all entries, it can be documented through reliable quantitative analytical data that kaersutite crystals with an identical appearance to those uploaded to the database can be found. There are however none of the uploaded specimens that are accompanied with analytical data proving that the individual cystal contains sufficient Ti to qualify as kaersutite. In these cases, I have followed the recommenations from the IMA Amphibole Subcommittee and used the term kaersutitic amphibole in the photo captions thus including true kaersutite, titanian pargasite, titanian magnesiohastingsite, and possibly also other closely related titanian amphiboles.

The kaersutite-series amphiboles are not particulary sought after by collectors, whether museums or private, as they are rarely much for the eye, and notoriously difficult to identify. For petrologists and scientists with an interest in mantle processes or special volcanic events, kaersutitic amphiboles are more interesting, and there is quite a lot of litterature available describing the genesis and chemistry of these amphiboles. Kaersutitc amphiboles are also much studied to understand the relationsship between ferrous and ferric iron as well as the role of Titanium in the amphibole molecule. It is also this relationsship that accounts for the variations distinguishing between kaersutite and ferrokaersutite, with ferrokaersutite being the rarer of the two.

Literature:

MCCUBBIN, Francis M.1, NEKVASIL, Hanna1, LINDSLEY, Donald H.1, and HANSKI, Eero J.(2006): NEW INSIGHTS INTO USING KAERSUTITE (TI-RICH AMPHIBOLE) AS A PETROGENETIC TOOL: AN EXPERIMENTAL INVESTIGATION, Paper No. 118-18, Philadelphia Annual Meeting

M. Darby Dyar, Stephen J. Mackwell, Ann V. McGuire, Laura R. Cross, J.David Robertson (1993): Crystal chemistry of Fe3+ and H+ in mantle kaersutite: Implications for mantle metasomatism, American Mineralogist, Volume 78, pages 968-979

Allison B. Connor (2000): THE MINERAL KAERSUTITE AND ITS OCCURRENCES, Senior thesis,Ohio State University


Kaersutite
Australia
Victoria, City of Greater Geelong , Anakie,Mount Anakie

kaersutitic amphibole, 4,2cm crystal© Judy Rowe


Mount Anakie belongs to the Newer Basalt Province in Victoria and South Australia. This province hosts a large variety of magma types, seemingly without any clear compositional progression. Some of the magmas are characterized by the occurrence of megacrysts in the form of sometimes “unusually large crystals”, believed to have formed in fractionation of liquid magma in mantel conditions.

Mount Anakie is the largest and northernmost of 4 aligned eruption points over a distance of 5km and is considered the most interesting of these scoria cones due to the presence of kaersuite megacrysts in nepheline mugearite host rock.

I have not found any maximum size for the kaersutite.

An analysis published in "Rock forming minerals, Volume 2" shows a Ti content of 0,632 afu (5,8%wt).

Literature:

J.F.G. Wilkinson and H.D. Hensel (1991): An analcime mugearite- megacryst association from north-east New South Wales: implications for high pressure amphibole dominated fractionation of alkaline magmas.
Contrib Mineral Petrol

Irving, A. J. (1974): Megacrysts from the Newer Basalts and Other Basaltic Rocks of Southeastern Australia. Geological Society of America Bulletin 85, 1503-1514.


Kaersutite
Czech Republic
Bohemia (Böhmen; Boehmen), Ústí Region, Bílina (Bilin), Lukov u Bíliny (Lukow)

Kaersutitic amphibole 1,8 cm wide crystal © Jakub Jirásek


Macroscopic (>2 mm) kaersutite phenocrysts can be found at several locations in the area, reaching sizes up to several cm mostly in the alkaline basaltic rocks, and kaersutitic amphibole is found in more than 70% of the more than 1000 alkaline dykes radially arranged to the main volcanic centre of the Ceske stredohori,

J. Ulrych has kindly provided analytical data from Lukov and several other locations related to the České Středohoří Mts. volcanic centre. The Ti content ranges from 4.24-5.29wt% placing these amphiboles at or near the titanian pargasite-kaersutite borderline of 0.5 pfu Ti.

Literature:
Bilina town association of Nature Sciences
Personal communication . J. Ulrych and M. Fillippi, Institute of Geology, Academy of Sciences of the Czech Republic, or shortened Institute of Geology, Acad. Sci. CR




Kaersutite
Czech Republic
Bohemia (Böhmen; Boehmen), Central Bohemia Region, Nymburk District, Seletice (Sulotice; Sulotitz; Sulloditz)

Kaersutitic amphibole 3cm © M. Filippi and P. Magdík
Kaersutitic amphibole 3,5cm crystal © M. Filippi and P. Magdík



Several locations near the Suletice village was described by Hibsch (1934). He is listing references back to 1903 for kaersutitic amphibole, but the knowledge of these localities may predate even these early references.

“Plundrichs Kuppe” Hill

The Plundrichs Kuppe Hill locality (SE of Suletice) is one of many locations for kaersutitic amphibole of the Ceske Stredohori Mts. Hornblendes are concentrated especially in the marginal porous part of the basaltic body.
Free kaersutitic amphibole and clinopyroxene crystals (“augites”) were collected in 1970’s on the fields below the Plundrich’s Kuppe Hill near the road to Homole village. The size of perfect columnar crystals of kaersutitic amphibole are up to 2.5 cm.

“Mückenhübel” ( Mückenkübel, Mickenhübel)
The Mückenhübel locality (ESE of Suletice) is one of the most traditional localities of kaersutitic amphiboles and clinopyroxenes (“augites”) up to more than 1 cm large in the Ceske Stredohori Mts.They originate from the tuffaceous (?) marginal part of a tephritic flow (Hibsch 1934).

The locality Mückenhübel was lost for a long time, but it was re-discovered by a coincident in 1996, when amphibole crystals was found in soil outside badger burrows. A more systematic approach revealed well formed crystals of kaersutititc amphibole and clinopyroxenes in tuff outcrops in a 20 by 40 m area. The amphibole crystals are unevenly distributed in the rock.

The amphibole is, at this location much more common than clinopyroxene and also reaches larger sizes. The size of the crystals varies from several mm to 2 cm, rarely up to 3-4 cm. In contrast, the size of clinopyroxene crystals exceeding 1 cm.

This is currently one of the more productive locations for kaersutitic amphibole and recent specimens from here are represented in collections across the central Europe.

In addition kaersutitic amphibole crystals can be found in other localities near Suletice ( 5-20km away), such as:

- Kostomlaty pod Milesovkou (up to 7 cm large crystals but often quickly disintegrating) in altered dyke (about 10 m) exposed in an abandoned coal pit

- Holomer in Usti nad Labem in altered volcanic breccia of a volcanic chimney

- Lukov, see separate entry.

- Kaersutiteic amphiboles occur commonly in phenocrysts (2 to 30 mm) of prevailing part of alkaline dyke rocks (lamprophyre, semilamptrophyre, leucocratic deravatives as bostonite) forming swarms (~1000 dykes) radially arranged to the main intrusive centre of the Ceske Stredohori Mts. in Roztoky (e.g., Techlovice and Dobkovice quarries)



Literature:

Hibsch JE (1934): Die Minerale des Böhmischen Mittelgebirges .- Gustav Fischer Verlag, Jena, 196 p.

Radon M. (1996): Current status of some sites of zeolites in the Czech Central.- Mineral, IV, 2, 85-89.

Cajz V (2003): Dyke Swarm Pattern and Tectonics in the České Středohoří Mts. Volcanic Centre, Ohře (Eger) Rift, Central Europe (Starting Points for Further Research). - Geolines, 15, 15/22.

M. Fillippi: [home.gli.cas.cz] (Mückenhübel locality only)



Kaersutite
Czech Republic

Bohemia (Böhmen; Boehmen), Plzeň Region, Černošín (Tschernoschin), Vlčí hora

Kaersutitic amphibole 3cm wide crystal group © M. Filippi


Kaersutitic amphibole 18 cm crystal© M. Filippi
Kaersutitic amphibole 10 cm crystal © M. Filippi


“The Vlčí Hora Hill (704 m) locality by Černošín close to Stříbro is a complex volcanic body in Western Bohemia formed in Miocene (11.7 Ma).

Two coexisting cogenetic volcanic series have been recognized in the broad area of West Bohemia : (i) weakly alkaline series basanite – trachybasalt – (basaltic) trachyandesite – trachyte – rhyolite (15.9-11.4 Ma) and (ii) strongly alkaline series olivine nephelinite – tephrite (16.5-8.3 Ma).

Vlčí Hora Hill belongs to the weakly alkaline series, and kaersutitic amphibole has been found both in basanitic rocks (prevalenty xenocrysts) and their tuffs (free perfect crystals) often together with clinopyroxene (“augite” de facto diopside) crystals. Smaller crystal of kaersutite occur also in near village Resanov in breccia filling of a chimney. Phenocrysts of kaersutite occur also in trachyandesitic rocks of the weakly alkaline series.

It is the quantity, size and development of kaersutitic amphibole and clinoporyxene crystals that has made this location known by collectors and scientists alike. Perfectly developed ,slightly molted and pitted kaersutitic amphiboles in sizes up to 15 cm has been found, normally rimmed by clinopyroxene and titanian magnetite. Kaersutitic amphibole is usually found as single crystals, however, random intergrowths of several crystals may be found.

The kaersutitic amphiboles from Vlčí Hora is amongst the most oxidized amphiboles known, with Fe3/Fe2 ratios between 7-37. They are also rich in titanium, containing between 4.28-4.63 wt% thus being intermediate between ferroan-oxypargasite and kaersutite with both minerals present. It is very tempting to follow J. Ulrych’s thoughts that the T i>0,5pfu requirement in the definition of kaersutite sets an arbitrary line and “separates genetically uniform hornblendes even within one locality into kaersutite and ferro-pargasite. Hence, the adoption of a limit characterized by 0.3 pfu Ti seems to be at some localities more suitable”

Pyroxene (augite) is very often mineral at this locality. It forms up to circa 8 cm long crystals, often grown into polycrystalline aggregates.

Partly altered/transformed? olivine (forsterite) is characteristic mineral for the locality. It occurs as up to 3 cm large well-developed crystals which are often grown into the augite crystals. Other macroscopic minerals at the locality are: phlogopite , hyalite, phillipsite and aragonite.”

Similar amphibole from Vlčí Hora has also been analaysed as titanian pargasite (tschermakite?) by Pavel Kartashov:

K0.34(Ca1.30Na0.69)1.99(Mg3.45Fe3+0.64Al0.57Ti0.34)5.00[(Si5.51Al2.49)8.00O22 ]O0.52.


Literature:

J. ULRYCH1, J. K. NOVÁK1, F. E. LLOYD2, K. BALOGH3, GYÖRGY BUDA (2002): ROCK-FORMING MINERALS OF ALKALINE VOLCANIC SERIES ASSOCIATED WITH THE CHEB-DOMAŽLICE GRABEN, WEST BOHEMIA
Acta Mineralogica-Petrographica, Vol. 43, pp. 1-18

Z. Jirák ; F. Pechar; S. Vratislav(1986): Distribution of Cations and the Proton Location in Kaersutite.
Crystal Research and Technology 21 (12), pg. 1517-1519

Jaromír Ulrych (1986): Oxykaersutite from the Vlčí hora Hill near Černošín, West Bohemia



Kaersutite
Germany
Rhineland-Palatinate , Eifel Mts , Andernach , Kruft , Korretsberg Mt.

Kaersutitic amphibole, 10mm specimen© C.H.M.-Schäfer


The Eifel area lies in Western Germany, near the borders to Belgium and Luxembourg. This region is one of the most interesting areas in Europe for collectors of microcrystals. This is due to relatively recent tectonic events (the last 430.000 years), leading both to rifting and volcanic activity. A large number of vulcanoes are in the area, with the Laacher See(13000 years old) as the youngest. An annual landlift of 1-2mm shows that the area may still be active.

Titanian amphiboles can be found as phenocrysts in the volcanic rocks in the Eifel lavas. Although various pyroxenes are more common as phenocrysts also the amphiboles can be found as well formed crystals embedded in the lava rocks.

The titanian amphiboles from the Eifel area can be either titanian pargasite, kaersutite or titanian magnesiohastingsite.

Litterature:

Cliff S. J. Shawa and Jimena Eyzaguirre (2000) Origin of megacrysts in the mafic alkaline lavas of the West Eifel volcanic field, Germany, Lithos, Volume 50, Issues 1-3

57Fe Mössbauer study of volcanic hornblende (1975) Chemical Physics Letters, Volume 30, Issue 3. Pages 403-405

M. Darby Dyar, Stephen J. Mackwell, Ann V. McGuire, Laura R. Cross, J.David Robertson (1993): Crystal chemistry of Fe3+ and H+ in mantle kaersutite: Implications for mantle metasomatism, American Mineralogist, Volume 78, pages 968-979

Deer, Howie, Zussman, (1997): Rock forming minerals, Double-chain silicates

Leake, (1968): A Cataloge of analysed calciferous and subcalciferous amphiboles...
(cataloge of recalculated and renamed amphibole analyses that have been published post 1890)


Kaersutite
Germany
Rhineland-Palatinate , Eifel Mts, Mendig, Bell, Rothenberg Mt. (Rothenberg quarry)

Kaersutitic amphibole 35mm FOV© C.H.M.-Schäfer

See text above.


Kaersutite
Greenland
Kitaa (West Greenland) Province, Uummannaq (Umanak) Firth , Qaersut (Kaersut)

Kaersutite 50mm FOV© C.H.M.-Schäfer


Qaersut is a small, remote village on the east coast of Greenland, and the type locality of kaersutite. The Qaersut amphibole was first described as a new mineral by Lorenzen (1884) on the account of its high Ti content. It took some time before kaersutite was acknowledged as a separate species as it’s optical properties was inseparable from other amphiboles, and chemistry was, at the time, one of many characteristics defining a mineral species.

Kaersutite was found in a nearly horizontal, 50m thick peridotite (picrite) sill penetrating Devonian sandstone. The peridotite sill is not homogenous, having some layers enriched in augite and a 1-2m wide doleritic band in the centre.
“In addition, there are numerous segregations of kaersutite-bearing pegmatite comprising a horizontal sheet 35-40cm thick traversing the upper portion of the sill” (Benson).

Kaersuitte is found as several cm long elongated crystals embedded in feldspar. Published analytical data from this rather unusual occurance shows a Ti content between 0,9 and 1,2 afu or +/- 10%wt TiO2.

Litterature:

Deer, Howie, Zussman, (1997): Rock forming minerals, Double-chain silicates
Benson, (1939): Mineralogical notes from the University of Otago, N.Z. No 3: Kaersutite and other brown amphiboles in the Cainozoic igneous rocks of the Dunedin district.


Kaersutite
Italy
Trentino-Alto Adige , Trento Province , Fiemme Valley , Predazzo

Kaersutitic amphibole 30mm crystal© Simone Citon
Kaersutitic amphibole 12mm crystal© G.Fraccaro



Kaersutitic amphibole can be found as well developed crystals in a calc-alkali suite of shallow intrusions. I have found no analytical data and will need some help for this location.

Litterature:

Demartin, F., Campostrini, I., Grisotto, M., Grisotto, L. (2006): I Cancozzoli. Una classica località presso Predazzo, Val di Fiemme, Trento. Rivista Mineralogica Italiana, 30, 166-177.


Kaersutite
Italy
Sicily, Catania Province, Etna Volcanic Complex, Mt Etna

Kaersutitic amphibole 7mm crystal© Enrico Bonacina


Mt Etna is the largest active volcano in Europe today. The volcano reaches and altitude of 3315m and it's lavas covers 1260 km2. The 600.000 year volcanic history is divided in four main evaluation stages:

1st stage: (580 to 225 ka) tholeiitic basalts which today can be found in outcrops out as pillow-lavas, hyaloclastites
and sills along the Ionian Sea coast north of Catania.

2nd stage: (220 to 96 ka) The lava composition changes from tholeiitic to Na-alkaline (Branca et al. 2004). A number of central volcanoes (Ancient Alkaline Centres or Timpe Volcanoes) were constructed over a time span of about 100 ka (172 to 96 ka), and their remnants mainly crop out along the present-day margin of Etna. It is in these ancient lavas kaersutitic amphibole can be found as well formed crystals. Published data by Rruff.org of an amphibole crystal gives a kaersutite composition w/ Ti= 0,64afu.

3rd stage: (80-60ka) A series of effusive and explosive eruptions built a series of successive cones Successively, the so-called Trifoglietto unit

4th stage: (60ka-present): The building of the current stratovolacano.

During the various eruptive stages, the composition of the amphiboles have changed, from kaersutitic amphiboles in the ancient stage 2, via pargasites to magnesiohastingsite in the latest 2001/2002 eruption. Correct identification of an Etna amphibole should consequently be based on a reliable analysis of the crystal.

Litterature:
Angelo Peccerillo (2005): Plio-Quaternary Volcanism in Italy, Springer Verlag, Chapter 8 Sicily.

M. Viccaro, C. Ferlito and R.Cristofolini (2007): Amphibole crystallization in the Etnean feeding system: mineral chemistry and trace element partitioning between Mg-hastingsite and alkali basaltic melt (2007)
Eur. J. Mineral. 19, 499–511


Kaersutite
New Zealand
South Island, Otago, Kakanui

Kaersutite constitutes an important part of the ultramafic inclusions in the mineral breccia at Kakanui. It is associated with garnet, clinopyroxene and magnetite. The mineral breccia is a mantle-sourced diatreme with associated marine reworked volcaniclastics. Mantle xenoliths include lherzolite and garnet pyroxenites occurring with megacrysts of garnet, clinopyroxene, kaersutite, and feldspar.

Kaersutite usually occurs as irregular crystals enclosed in the matrix. Occationally, rounded, simingly “polished” crystals up to 5 cm in diameter and 15 cm length can be found. The “polished surface is probably due to friction in the mineral breccia.

Analytical data suggest that the Ti content in the kaersutite lies between 4,98 and 5,87 wt% TiO2

Litterature:
Kenzo Yagi, Yu Hariya, Kosuke Onuma and Noriko Fukushima (1975): Stability relations of kaersutite,
Jour. Fac. Sci. Hokkaido Univ., Ser IV, Vol 16, no 4

R. Clearland Wallace (1977): Anorthoclase-calcite rodding within a kaersutite xenocryst from the Kakanui Mineral Breccia. New Zealand
American Mineralogist, Volume 62


Kaersutite
USA
Arizona, Otago, Mohave Co., Minnesota District,Hoover Dam vicinity - 8 miles South

Kaersutite, 8x4cm spec.© Jorge M. Alves


Kaersutite can be found as up to 10cm large megacrysts in camponite dikes. The best known dyke, and also the source of most of the Hoover (Boulder) Dam kaersutites come from a road cut some 8 miles south of the dam itself. The dyke is 4ft wide and the near vertical orientation give a 12ft exposure in the road cut. Kaersutite can also be found in other camptonite dikes in the area.

The kaersutite megacrysts gets larger towards the centre of the dyke. It is believed that rapid cooling towards the walls of the dyke trapped the volatile elements within the dyke, thus allowing larger kaersutites to form towards the centre of the dyke. The kaersutite seems to have grown rather rapidly ( Campell and Schenk suggests 25 days)
Published data seems to indicate a Ti content ranging from 5,49-5,78%wt TiO2

Litterature:
Ian Campell and Edward T. Schenk (1950): Camptonite dikes near Boulder Dam, Arizona.(1950), American mineralogist volume 35.
Michael O.Garcia, David W. Muenow, Norman W. K. Liu (1980): Volatiles in Ti-rich amphibole megacrysts, southwest USA, American Mineralogist, Volume 65


Olav Revheim June 2011

Click here to view Best Minerals K , and here for Best Minerals A to Z and here for Fast Navigation for finished Best Minerals articles.



Edited 28 time(s). Last edit at 03/25/2012 09:02AM by Olav Revheim.
avatar Re: Kaersutite-series
May 20, 2011 02:28PM
    
The first, what is necessary to explain here, is the simple thing - kaersutite is rare mineral. In other words most of "kaersutites" represented here aren't kaersutites. Basaltic hornblende with 3-4 mas.% of TiO2 isn't kaersutite.
I had analysed all accessible to me kaersutites, and found that all them are different amphiboles with too low Ti content to populate at least 0.5 f.u. For the moment I haven't any kaersutite in my collection.
You should to understand, if you have some amphibole from locality, where kaersutite was determined and described, it don't means, that you have real kaersutite. If you'll read these descriptions, you'll found, that kaersutites usually form micro-size, bad individualized grains in rock or only microscopic zones in fenocrysts in it. In other words, if you have large shining crystal - it isn't kaersutite with 99.5% probability. Ti in high quantities is VERY rare in amphiboles, so kaersutite is first of all small mineral.
And these orange "kaersutites" from Eifel are VERY suspicious for me for whole row of reasons.

The main idea of the post is, if exactly your kaersutite specimen wasn't analyticaly confirmed - YOU HAVEN'T KAERSUTITE.
If you don't believe me, try to check your crystals of kaersutite, and we'll see, whom it will turned out.;)



Edited 1 time(s). Last edit at 05/20/2011 02:36PM by Pavel Kartashov.
avatar Re: Kaersutite-series
May 20, 2011 03:17PM
I think based on what Pavel says, perhaps we should not have a 'best of' article for this mineral.
avatar Re: Kaersutite-series
May 20, 2011 03:21PM
    
The single confirmed one able to become the best.;)
avatar Re: Kaersutite-series
May 20, 2011 05:09PM
clearly :)
Re: Kaersutite-series
May 20, 2011 08:06PM
    
Thanks guys for starting this discussion, I am slightly surpised that it took so long. smileys with beer.

If I read Pavel Karthasov's first post correctly the following are the core statements:

1) Kaersutite is a rare mineral and most "kaersutite" photos in the database are not and cannot be kaersutite
2) The obsolete term basaltic hornblende is NOT equivalent with the IMA mineral kaersutite.
3) Individual locations will most likely contain more than one amphibole species, and it is not good practice to name an amphibole kaersutite just because it has been described from a location.
4) The orange Eifel kaersutites are dubious.
5) If a kaersuite specimen is not confirmed by adequate testing, it should not be labelled kaersuite.

The conclusion may be obvious in that there should not be any kaersuite "best of" article.

It is tempting to follow this logic one step further: There should not be any "best of" article for any of the amphibole minerals, simply because statements 3) and 5) above are valid for all amphibole minerals. Consequently the word "mess" may be appropriate for the Mindat entries for most amphibole species.

Only a fraction of the amphibole group minerals uploaded to mindat have been adequately tested. Most of the good amphibole location carries more than one similar (if not identical) looking species, with the Grenville marbles and skarns on the US East coast and Ontario, Canada as a prime example. In reality, almost every one of the amphbole specimens collected should be tested individually to correctly identify it ( provided it is not zoned), not taking into consideration that adequate testing will cost more than the value of even the best amphibole specimen.

To add to this, the re-definition of the amphibole group minerals starting by Leake's "Nomenclature of amphiboles" from 1978 has made most older litterature references obsolete. Kaersuite was one of them. Before 1978, Ti>0,5 f.u in the C position was no requirement, so minerals referenced as kaersutite before 1978 may not be kaersutite now.

Despite these obvious shortcomings I think the "best of" articles on the amphiboles may be valuable because:
1) Some of the best photos of amphibole minerals are highlighted in these articles and their idenitifcation are checked towards available litterature and they are exposed for a Mindat community peer review.
2) The text should reference litterature, analytical work and/or doubts regarding the identification of these minerals ( see the other articles)
3) These articles may hopefully add to the general knowledge on amphibole minerals, thus contributing to the overall goal for the best of section in the message board. ( They certainly have increased my knowledge, although that didn't require much).

With regards to the kaersutite specific issues addressed:

1) It appears that at least some of these locations may be genuine, such as
- Mount Anakie, Australia ( Litterature mentions kaersutite megacrusts)
- Mt Etna - seeRRUFF- kaersutite
- and probably one or more of the German locations.

4) The orange amphiboles from Eifel are discussed in the messageboard before : Eifel amphibole

To conclude this rather long post, I think there are two options for the amphibole group, either leave it untouched because it is too complex or try to address some of the known facts and uncertainties. I think even an article with ten dubious locations have more value than no article povided the uncertanties in the identification are highlighted and justified.

I think Pavel Khartasov's post adds value to the article rather than making it obsolete, but I have no problems in seeing and respecting the opposite view.

(:P)

Olav
avatar Re: Kaersutite-series
May 20, 2011 08:21PM
Without wanting to necessarily back one side or the other on this debate, I did wonder whether it would be better to do one 'Best of' article just on the Amphiboles in general, rather than trying to detail every different species within the grouping (which I'm sure will all change around again within 20 years).

Terms such as "hornblende" are perfectly sensible for unanalysed black amphiboles. As Pavel says, it's unwise to assume your amphibole is species X just because another from that locality has been analysed as it.

yes, the same problem could occur for almost any 'best-of' article, but I think things such as amphiboles, tourmaline etc are more likely to suffer these problems.


We also have the problem now of having to go back to the galleries and, effectively, unapprove all these photos, or switch them to hornblende or just 'amphibole'. Not sure what to do with the Eifel ones, not my area of knowledge.

Jolyon
avatar Re: Kaersutite-series
May 21, 2011 11:26AM
I think that an article on Kaersutite might be worthwhile because there are so many specimens out there with that name. The article could be done, but with Pavels comments and others as the lead in to the article. The article could still show all the images we have in the database for that mineral, but in the captions Kaersuite name would in each instance be followed by a question mark or a double question mark with the exception of the one or two that may have been adequately analysed. Probably the same information as we end up putting in the lead in to this article should also be placed in the Kaersuite page and at the very least, all suspect images should have a question make placed after their name in the caption along with a link to the Kaersuite page that explains the mess and the considerable uncertainties. What a can of worms! At least we could try this solution and let it stand till it becomes obvious that it is doing more harm than good.

Rock Currier
Crystals not pistols.



Edited 1 time(s). Last edit at 05/21/2011 11:27AM by Rock Currier.
avatar Re: Kaersutite-series
May 21, 2011 11:33AM
I disagree - we can't show photos of a mineral on a 'best-of' page where there is serious doubt about the identification process.

To show it with a ? is worse than not showing it at all in my opinion.

The most important thing we have to do is improve the accuracy of the data we have, including mineral identifications. Making sure we have enough photos for a nice article is a secondary concern.

The debate about whether a mineral is Kaersutite or not belongs on the Kaersutite page on mindat, not in this article (in my view).

Jolyon
avatar Re: Kaersutite-series
May 21, 2011 11:55AM
Olav,
What say you? Jolyon may be right. Perhaps others will also have opinions.

Rock Currier
Crystals not pistols.
Re: Kaersutite-series
May 21, 2011 04:07PM
If specimens from a locality have traditionally been labelled "kaersutite", but might not be, or might only partially be, then perhaps the Best Minerals pages is a good place to mention this, along with approprate explanations and caveats, otherwise we'll get endless questions posted about "Why isn't this locality mentioned here?".

100% accurate identification is a goal, but often unachieved. If we start cutting stuff because the ID might be wrong, we'd have to cut an awful lot of tourmalines, sulphosalts, etc, etc. In my opinion better to mention them if they are "famous", but add the caveat. It might stimulate further investigation which would never happen if we didn't mention the doubts.

Then with amphiboles, tourmalines, sulphosalts, etc we have the whole can of worms about photos of crystals with multi-species zoning, and the visible exterior zone being.... who knows what? Again, presentation (with explanations) is more informative than simply sweeping them under the rug and hiding them.



Edited 2 time(s). Last edit at 05/21/2011 04:09PM by Alfredo Petrov.
Re: Kaersutite-series
May 21, 2011 04:55PM
    
Many issues have been raised in this thread, and I think that this discussion will eventually contribute to better "best of" articles and a more mature "best of" consept, and it is kind difficult to address all of them at once.

I tend to agree with Jolyon in that these articles should not include entries where there are serieous doubt on the identification of the species. For the articles with a "first draft" status I have only included entries where I am reasonably confident on the ID, and improving accuracy of information should one of the main objectives for the "best of" articles.

I also think that these articles while "under construction" is a good place to discuss the mineral and the database entries. Some valuable information has surfaced in the "best of" threads that probably would not surfaced in any other forum.

I strongly disagree in grouping all amphiboles into one article. Despite the dificulties in correctly identifying amphiboles, there are surprisingly many entries that are followed with analytical data or solid litterature references. I think that "giving up" on the amphibole group and thus ignoring the tremendous diversity in this group defies our human curiousity and the vast amount of information that are available on these specimens.

As for the kaersutite-series minerals I have found so much litterature that I am confident that at least some of the included entries are correct, thus in my mind justifying the article. In the process of refining the article from "illustrated placeholder" to first draft, I am also confident that some of the entries will be removed.

(:P)

Olav
avatar Re: Kaersutite-series
May 21, 2011 08:27PM
The problem with listing all the photos here is it becomes self-reinforcing - "my specimen must be a kaersutite because similar material was listed on mindat from this locality, even in the best-of page" - and then more specimen photos are uploaded with the same identification.

The problem, as Pavel has pointed out, is that there MAY be a genuine valid record of kaersutite from any number of localities - but that may have been an unusual find, and doesn't necessarily mean that every black amphibole from that locality is kaersutite.

I think for certain mineral species, and this is one of them, we should ONLY include photos of specimens that have been directly analysed - unless there is a reasonable reference to show that the species is abundant at a particular locality, or that other species of amphibole are unknown there.

I would rather have 2 photos that we really KNOW are kaersutite than 20 that might be.

And the argument that we shouldn't do it because it's too difficult, and it means we have to change a lot of other things, such as the sulfosalts, doesn't fit well with me either. We should do it because it's right, not because it's easy or not.

Jolyon
Re: Kaersutite-series
May 21, 2011 08:59PM
    
Do you have any issues or comments on the other amphibole group articles?

Tschermakite-series
Tremolite
Edenite
Hastingsite
Hornblende

Olav



Edited 1 time(s). Last edit at 05/21/2011 09:37PM by Olav Revheim.
avatar Re: Kaersutite-series
May 22, 2011 09:28AM
Jolyon,
In an ideal world, you are correct. I can understand that you feel that an article in best minerals about this particular amphabole, given the ambiguity about its analysis and that of other amphaboles, is just increasing the problem. OK, if we want to make things better say, starting here with this mineral, what steps should we take to clean up the images that are already in the database and what do we do to keep things from getting worse as people upload more images of amphaboles to the database. Should not the image upload page be changed to discourage or limit people from uploading those kinds of images without proper analysis to back them up? How does this square with your general philosophy to allow people to upload images freely? More stringent vetting of submitted images? In that case someone needs to write up guidelines for not only amphaboles, but pyroxenes, micas, amphaboles, tourmaline and probably about ten other groups. If we are going to clean up the images as far as species are concerned we are going to need a lot more people working on cleaning up the captions and even the species that they are listed as. This will, unless current policy changes involve sending out thousands of complaint letters. And we don't yet have an augmented permissions protocol to allow additional non managers to help with this work. Do we need to set up working committees on these problem groups like the IMA? Should we petition the existing committees of the IMA to become involved in this? I feel that best minerals like Olav's with question marks and suitable warnings and comments is certainly better than anything we have now.

Rock Currier
Crystals not pistols.
avatar Re: Kaersutite-series
May 22, 2011 09:53AM
It all depends whether we want a page of "Photos of minerals that fit within the official IMA definition of what kaersutite is", or a page of "Photos of specimens that are described as kaersutite by their owners".

Whilst the second gives a nicer gallery of photos, I still don't see what scientific merit it has.

However...

I'm not an expert on amphiboles and it would be wrong for me to say exactly what the best approach is in this case.

If the general consensus is that this page should be kept as it is, with just words of caution about the photos not necessarily being the mineral at all, then I'll accept it.



Edited 1 time(s). Last edit at 05/22/2011 10:01AM by Jolyon Ralph.
avatar Re: Kaersutite-series
May 22, 2011 10:25AM
I must agree with Jolyon - a lot of people rely on this site for classifying their specimens, and if there is a doubt its better to just say that its an amphibole (possibly close to kaesutite or a titanium-rich magnesiohornblende etc). But a best of page for the hornblende subgroup may be quite acceptable?

Regards,
Ralph
Re: Kaersutite-series
May 22, 2011 11:12AM
    
Of course the information in these articles should be as correct as possible, noone has suggested anything else. To improve what I am doing I would very much like som specific input, such as:

1) Does anyone ( Pavel?) have analytical data from any of the listed locations suggesting that the "kaersutite" entries are not kaersutite?

2) Are there any entries in this or the other amphibole group articles that are misleading or incorrect? Any information will be appreciated. How are the quality of information in these articles compared with the Mindat database in general?

3) How should one define the "Hornblende Subgroup"?

4) What is the "scientific merit" of including all the 200 (or thereabout) amphibole species in one amphiobole group article?

;)

Olav



Edited 1 time(s). Last edit at 05/22/2011 11:27AM by Olav Revheim.
avatar Re: Kaersutite-series
May 22, 2011 11:34AM
> 1) Does anyone ( Pavel?) have analytical data from any of the listed locations suggesting
> that the "kaersutite" entries are not kaersutite?

The burden of proof should be on proving these specimens are what they claim to be, not on disproving them!

It is one thing for an article to say "We tested a sample from X and it was Kaersutite", but if it says "we tested 100 different samples of amphibole from locality X and they were all kaersutite" - that is VERY different!

> 2) Are there any entries in this or the other amphibole group articles that are misleading or incorrect?
>Any information will be appreciated. How are the quality of information in these articles compared with
> the Mindat database in general?

I suspect it might be quite widespread - I was worried about this issue long before the issue on kaersutite came up!

> 4) What is the "scientific merit" of including all the 200 (or thereabout) amphibole species in
> one amphiobole group article?

It's tricky - and not necessarily something that would work well (it would be too big). On reflection probably it is better to have individual pages for each species (or for groups of closely related species as we are doing now) .

I think the compromise based on views above is to do this - keep the article as it is, but restrict the locality entries to those that we have good verifiable scientific references to back up the claims of the mineral.

Jolyon
avatar Re: Kaersutite-series
May 22, 2011 12:00PM
Olav,
I would suggest you go ahead but heavily lard the articles with references as to the possible inaccuracy of some of the names and then people can come along here and tell you how badly you have screwed up and how these matters should be addressed, and others will say what a great job you are doing, and perhaps after a lot of discussion and changes as we go along, God willing, a consensus will be achieved on how we should write these articles and through this we will be able to improve what information we place on the articles for these minerals and how far we should go in correcting the captions on various images that are already uploaded. After you are satisfied with the lead in description of the species and no one kicks about it any more you should take a look at the page for this mineral and see if the general text about that mineral needs changing. If it does you could propose propose text, perhaps based on what you have written here, to replace what is written on the page for that mineral.

I never told you this would be easy and now you can understand why I was so grateful that you undertook this job. You are a braver man than I. I do think we should hold the images we use here in the best minerals articles up to a higher standard of accuracy than those in the general database and have no hesitation in switching out offending images or moving them to correct localities as better information is brought to our attention, but I don't think I am telling you anything you don't already agree with and practice. Now tell me what innocent person we can hornswoggle into doing the micas!

Rock Currier
Crystals not pistols.
Author:

Your Email:


Subject:


Attachments:
  • Valid attachments: jpg, gif, png, pdf
  • No file can be larger than 1000 KB
  • 3 more file(s) can be attached to this message

Spam prevention:
Please, enter the code that you see below in the input field. This is for blocking bots that try to post this form automatically. If the code is hard to read, then just try to guess it right. If you enter the wrong code, a new image is created and you get another chance to enter it right.
CAPTCHA
Message:
Mineral and/or Locality  
Search Google  
Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
Current server date and time: September 21, 2014 00:05:16
Mineral and Locality Search
Mineral:
and/or Locality:
Options
Fade toolbar when not in focusFix toolbar to bottom of page
Hide Social Media Links
Slideshow frame delay seconds