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Richterite series

Posted by Olav Revheim  
Richterite series
March 02, 2012 02:26PM
    
FIRST DRAFT


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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 richterite-series minerals belong to the amphibole group, see Amphibole Group main article for an overview of the group. The series contains the following minerals:

Ferrorichterite
Na(NaCa)Fe2+5(Si8 O22(OH)2

Fluoro-potassicrichterite
K(NaCa)Mg5Si8 O22F2

Fluororichterite
Na(NaCa)Mg5Si8 O22F2

Potassicrichterite
K(NaCa)Mg5Si8 O22(OH)2

Richterite
Na(NaCa)Mg5Si8 O22(OH)2

Fluororichterite 2.5 cm crystal © Maggie Wislon


The richterite series of minerals is part of the Sodic-Calcic Subgroup, having an intermediate composition between the calcic-subgroup and the sodic-subgroup. Being of an intermediate composition, this subgroup at some stage may be obsoleted, and many of its minerals, including the richterite series, may be discredited.

There is some debate about this, as the richterite-series can be considered an end-member series and it is a characteristic mineral in some alkaline rocks, such as lamproites, kimberlites, etc. It is in these rocks that richterites occur most frequently, but most often as minute grains in the rock groundmass and of very little interest for the average collector. These minerals also occur with arfvedsonite in carbonatites, but also most frequently as small grains in the rock.

World-wide, there are only three ocurrences that produce display specimens: Ontario, Canada; Koksha, Afghanistan and the Kedrovyi alkaline Massif, Russia. These three areas produce some of the most spectacular amphiboles that can be found, whether it is the up to 30cm long, doubly terminated black crystals from Ontario, the transparent golden richterites from Afghanistan or the blue jade-like material from Russia.

Richterite-series minerals form intermediate members both within the series and towards other amphiboles in the sodic-calcic subgroup (winchite series), and towards the calcic subgroup (tremolite and edenite series) and the sodic arfvedsonite-series. Many of the amphiboles found at the localities included in this text are such intermediate members, and some of the pictured specimens may not be the described richterite species.

In this article, I have tried to include all the richterite minerals and localities for each. Except for the three best locations mentioned above, the included localities are typical rather than best.


Richterite
Fluororichterite
Afghanistan
Badakhshan Province (Badakshan Province; Badahsan Province), Khash & Kuran Wa Munjan Districts, Koksha Valley (Kokscha Valley; Kokcha Valley), Kiran


Richterite 35 mm crystal© Christian Bracke
Richterite 5 cm crystal© Christian Bracke

Richterite 7.2 cm specimen© Christian Bracke
Richterite 39 mm crystal© C.Mercer

Richterite 25 mm crystal© Joseph A. Freilich, LLC
Richterite 29 mm crystal© Russell G. Rizzo


The beautiful transparent amphiboles from the Koksha Valley have been labeled both as winchite and richterite. It appears that these crystals are from a small find and are K- and F-rich richterites, without having sufficient K and/or F to be named as the more excotic richterite. SeeMindat message board

The earliest description of these crystals that I have found comes from Dudley Blauwet (2004): "He later indicated that some fine single gem crystals of yellow potassian fluorian richterite, often associated with sodalite, were found at a place which was a day’s walk to the backside of the mountain housing the main lapis mine" - i.e. near the Sar-e-Sang area. The association with sodalite (hackmanite) seems to be confirmed from photographed specimens at Mindat and other sites.

These crystals do not seem to be known by Shah Wali Faryad, who published several papers on the petrology from the Sar-e-Sang area from 2002 and onwards. On the contrary, he identifies (by microprobe) several other amphiboles from the rocks associated with the lapis lazuli occurrences near Sar-e-Sang. These rocks originate from "primary carbonate and evaporite mixture that result (in) formation of variegated mineral assemblages. In addition, metasomatic reactions between granite/pegmatite band adjacent carbonate carbonate-evaporite" have formed various mineral assemblages. These papers are worthwhile reading as they describe a very special geological environment with rare rocks and mineral assemblages.

Sodalite (which is associated with the richterite amphiboles) can only be found in what Faryad terms the 3rd stage metamorphosis in some calc-silicate rocks and mostly in the Na-Ca-K-rich rocks that carry lazulite, and it appears that these beautiful crystals were part of a relatively small find.

References:

Blauwet, Dudley (2005): The Road Goes on Forever: Mineral Adventures in Southwest Asia. Summer 2004, Axis, Vol. 1, No. 7. www.MineralogicalRecord.com

Shah Wali Faryad (2002): Metamorphic conditions and fluid compositions of scapolite bearing rocks from the lapis lazuli deposit at Sar-e-Sang, Afghanistan. Journal of Petrology, Vol. 43, No. 4, pp 725-747.


Richterite
Australia
Victoria, Macedon Ranges Shire, Mount Macedon, Camels Hump

Richterite FOV 3 mm© Judy Rowe


This richterite is from the “Camels Hump” peak on Mount Macedon, where it was found in trachyte lavas. The richterite seems to have crystallized from a peralkaline residual liquid rich in volatiles and can be found as micro-crystal in veins in the rock.

References:

Ferguson, A.K. (1978): Abstract: A mineralogical investigation of some trachytic lavas and associated pegmatoids from Camel's Hump and Turritable Falls, central Victoria. Journal of the Geological Society of Australia, Vol. 25, Issue 3-4.


Fluoropotassicrichterite
Australia
Western Australia, Derby-West Kimberley Shire, Kimberley, Noonkanbah sheep station, Walgidee Hills lamproite

Fluoropotassicrichterite 2 mm crystal fragment©


Potassic richterite occurs as a rock forming mineral in 20 Ma old lamproites in West Kimberly, Western Australia. The Walgidee Hills lamproite is relatively coarse grained and richterite grains up to a few mm can be found. The richterites from here are rich in K and Ti. I am not sure whether the K content is always sufficient to qualify the rictherite as a potassiumrichterite with K>0.5 apfu. the F content is not always determined and it is consequently uncertain whether F>OH is always true.

The richterite from Walgidee hills was originally described as a new species, magnophorite, but the material was later found to be potassiumrichterite.

References:

Mitchell, Roger H. and Bergman, Steven C. (1991): Petrology of Lamproites. Springer Verlag.

Prider, Rex T. (1940): New Mineral names. American Mineralogist, Vol. 25, No. 2, page 155.


Richterite
Fluorrichterite
Canada
Ontario, Haliburton Co., Monmouth Township, South ½ lot 14, concession 11, Gibsons Road East occurrence

Richterite 8 cm specimen© Maggie Wilson
Fluororichterite 6.7 cm crystal© MJB, 2009
Fluororichterite 5.5 m specimen©

The Gibson Road occurrence was reportedly discovered by a local collector, Steve Smith, around 1995. These richterites contain variable amounts of F and K. It appears that they normally have K<Na in the A position and F>OH.

Since the original discovery, the mineralized zone has been exposed over a much larger area. It consists of large crystals contained in, or weathered out of, calcite veins and pods in gneiss and amphibolite. All Canadian richterite locailites included in this article are of this type, and have been referred to as calcite vein-dykes.

The origin of the richterite-bearing calcite vein-dyke complexes are much debated, as their mineralogy and trace element chemistry differ from what would be expected from the commonly occurring (in that area) contact zone between metamorphosed marbles and the surrounding gneisses and amphibolites. Based upon their chemistry, it appears that they are metamorphosed carbonatite veins, and it is this origin that is responsible for the formation of richterite-series amphiboles rather than tremolite-magnesiohornblende-pargasite amphiboles that are more common in marbles and contact rocks of a metasedimentary origin.

The mineralogy of metasedimentary and metacarbonatite calcite veins are not very different, but Moecher et al. (1997) list the following characteristics for Ontario calcite vein-dykes of carbonatitic origin:

- The calcite is often of pinkish-orange color.
- Green/blue/colorless fluorapatite commonly constitutes a large (up to 20 modal%) portion of the rock.
- Small apatite grains embedded in mica often contain sufficient U/Th to form halos.
- Zircon and allanite are common accessory minerals.

These indicate a carbonatite origin for the calcite veins. For identifying the amphiboles found in the calcite veins, the origin of the rocks are important. For metasedimentary marbles, the amphibole is likely to be a calcic amphibole (tremolite/actinolite towards pargasite), whereas the amphiboles from metacarbonatites have a higher Na/Ca ratio and will normally be richterite-series, edenite-series or in rare cases as katophorite-series minerals. It should be noted that for all the Ontario locations listed here, it is quite probable that both richterite and fluororichterite, and possiby potassic-fluorrichterite, edenite and fluoroedenite, can be present, even within the same crystal, pocket or location, see Mindat message boad. In this text I have used the the richterite-series names listed in the mindat database and have not used the term "hornblende", as this should be reserved for the calcic amphiboles. By using hornblende for all dark amphiboles from metasedimentary and metacarbonatite origin, we would loose significant information on the amphibole's geological origin, chemistry and identification.

References:

David P. Moecher, Eric D. Anderson, Claudia A. Cook, and Klaus Mezger (1997): The petrogenesis of metamorphosed carbonatites in the Grenville Province, Ontario, Canadian Journal of Earth Science, Vol. 34.

Maggie Wilson (2010): Potassic-fluororichterite locality, Ontario. Mindat Messageboard.

MILLS, James G. Jr, ADANK, Kathryn M., and MYRVOLD, Christopher R(2003): CALCITE VEIN-DYKE COMPLEXES IN THE BANCROFT, ONTARIO REGION: EVIDENCE FOR A 930 MA CARBONATITIC INTRUSIVE EVENT IN THE GRENVILLE PROVINCE, ONTARIO (Abstract), Paper No. 222-7, Seattle Annual Meeting (November 2–5, 2003).


Fluorrichterite
Canada
Ontario, Haliburton Co., Monmouth Township, Tory Hill

Fluororichterite, 7.5 cm specimen© Dan Weinrich


There are several fluororichterite locations in the general Tory Hill area.


Fluororichterite
Canada
Ontario, Haliburton Co., Monmouth Township, Tory Hill, Hunter property

Fluororichterite 5 cm specimen© Maggie Wilson
Fluororichterite 5 cm specimen © David J. Eicher


The Hunter property is another locality for fluororichterite from calcite vein-dykes. This locality lies close to the Gibson Road locality and Bear Lake diggings and are part of the same geological environment.

References:

Maggie Wilson (2010): Potassic-fluororichterite locality Ontario, Mindat Messageboard.

Fluorrichterite
Canada
Ontario, Haliburton Co., Monmouth Township, Wilberforce,

Fluororichterite 5.2 cm crystal © Rob Lavinsky
Fluororichterite 3.5 cm crystal © 2001 John H. Betts
Fluororichterite 4.4 cm specimen© Rob Lavinsky

There are several fluororichterite bearing calcite dyke-veins in the Wilberforce area, and two are included in this text below. The fluororichterite vein-dykes are all found in the Central Metasedimentary Belt (CMSB) of the Grenville Orogeny. The sediments and volcanic rocks of the CMDB were originally deposited in an arc system outside the Laurentia between 1280 and 1250 million years ago. During the Grenville orogeny, these sediments was intruded by a multitude of igneous intrusions:

- 1280–1230 Ma gabbro and anorthosite
- 1280–1250 Ma “Elzevir” tonalite
- 1250–1240 Ma leucogranite
- 1090–1065 Ma syenite and granite
- 1070–1040 Ma carbonatite and fenite
- 1050–1030 Ma granitic pegmatite

The original rocks were metamorphosed to amphibolite-granulite facies. The calcite dyke-veins are younger than this, and it has been suggested that they are evidence of a younger (930 Ma) carbonatite intrusion.

The fluororichterite bearing calcite dyke-veins have a different origin than the usual calc-silicate rocks formed at the contact between marbles and surrounding gneisses.

References:

Ben A. van der Pluijm, Katherine A. Carlson (1989): Extension in the Central Metasedimentary Belt of the Ontario Grenville: Timing anf tectonic significance. Geology Vol. 17, pp 161-164.

S.D. Carr, R.M. Easton, R.A. Jamieson, and N.G. Culshaw (2000): Geologic transect across the Grenville orogen of Ontario and New York, Can. J. Earth Sci. 37: 193–216.

P.C. Thurston, H.R. Williams, R.H. Sutcliffe and G.M. Stott (ed.)(1991): Geology of Ontario. Ontario Geological Survey, Special Volume 4, parts 1 and 2.


Canada
Ontario, Haliburton Co., Monmouth Township, Wilberforce, Earle's Farm Fluororichterite occurrence

Fluororichterite 5.1 cm specimen© Dan & Diana Weinrich Minerals
Fluororichterite 2.9 cm crystal

Fluororichterite 11.6 cm crystal © David K. Joyce
Fluororichterite up to 2.0 cm crystal© Maggie Wilson


A calcite vein-dyke in gneiss. This locality was removed during road-widening prior to 1986, but specimens labelled with Earle's Farm are still widely available. Fluororichterite crystals were found embedded in calcite and were well formed, doubly terminated crystals exceeding 10 cm.


Canada
Ontario, Haliburton Co., Monmouth Township, Wilberforce, Essonville Fluoro-Richterite occurrence (Essonville Roadcut),

Fluororichterite 4 cm crystal © Filip Kopecky
Fluororichterite 2.8 x 2 cm specimen © Jay Vonderhey

Fluororichterite 1.5 cm specimen© Andrew Johns
Fluororichterite 3 cm crystal ©


Fluororichterite crystals are embedded in flesh-colored, massive calcite. The crystals can be quite large, up to 30 cm in length, and are usually well formed and terminated. The Essonville fluororichterite location has been known to collectors since the 1970s, and has since been heavily worked by rockhounds. It can be difficult to free undamaged crystals from the rock.

The crystal terminations can be one of two types. One form is flat, while the second is more complex with numerous faces creating shallow terminations. On rare occasions, the termination will give away the presence of twinning. Twin crystals will be obvious, showing well defined reentrant angles on the prism faces and sometimes even on the terminations of the crystals. Found both in the solid calcite matrix or within the surrounding soils, crystals of fluororichterite are common. Because they have formed as floater crystals in the calcite, they are almost always doubly terminated and, if collected properly, almost always damage free.

The mineralization at Essonville extends into private land. There is no collecting allowed (as of 2012), but guided tours are arranged, allowing visitors to see fluororichterite and other minerals in situ.

References:

Michal Adamowicz (2009): Collecting Rare Fluororichterite at the Essonville roadcut, Wilberforce. Mindat article.

Michael Walter: The Fluororichterite Occurence, Wilberforce, Ontario, Canada, geologicdesires.com.

John Etches: The Greenmantle Farm mineral occurence.


Fluororichterite
Germany
Rhineland-Palatinate, Eifel, Ettringen, Mayen, Bellerberg volcano, Caspar quarry

Fluororichterite 3 mm FOV© C.H.M.-Schäfer


The Caspar quarry is an active quarry (2012) near the Laacher See in the Eifel volcanic area. This is area is contains recent volcanic rocks of variuous compositions as well as a variety of xenoliths trapped in the lava. If the xenolith is large enough (about 1 cm or more), the result of the pneumatolytic alteration is a reaction rim surrounding the xenolith. The mineralization inside this reaction rim is quite different from that outside. Depending on the composition and other characteristics of the volcanic gas and depending on the type of xenolith (gneiss, sanidinite, Ca-rich xenoliths) different mineral associations occur.

Richterite occurs as honey-yellow acicular crystals in Na- and Mg-rich xenoliths deficient in Al with: roedderite/eifelite, obertiite dioside/aegirine, enstatite, tridymite and other minerals.

References:

FRANK C. HAWTHORNE,1,* MARK A. COOPER,1 JOEL D. GRICE,2 AND LUISA OTTOLINI3(2000):
A new anhydrous amphibole from the Eifel region, Germany: Description and crystal structure of obertiite, NaNa2(Mg3Fe3+Ti4+)Si8O22 American Mineralogist, Vol. 85, pp 236–241.

Chrisotof Schaefer (2007): Mindat message board.



Richterite
Fluoropotassicrichterite '
Potassicrichterite
Italy
Aosta Valley, Saint-Marcel, Prabornaz Mine (ex Praborna Mine)

Richterite FOV 1mm© luigi chiappino
Richterite 6 cm specimen©


The richterites of the Prabornaz mine is the result of a complex geological history. The original sea-bed basalts overlaid by manganese-reach and chert type sediments has undergone no less than four stages of metamorphosis (eclogite facies peak metamorphosis) giving an interesting mineralogy thoroughly investigated by mineralogists.

The richterite-series minerals occurs in the braunite/quartz ore zone as fibrous yellow-brown bundles and fans or as elongated pink crystals in fracture zones formed during retrograde blueschist facies metamorphosis. It should be noted that other amphiboles in both the calcic- sodic-calcic and sodic subgroup ( tremolite-richterite/winchite-glaucophane) and Mn-rich cummingtonite is also occuring at this location. Care should be taken when identifying these amphiboles.

References:

Annibale Mottana, William L. Griffin (1986): Crystal chemistry of two coexisting K-richterites from St. Marcel (Val d'Aosta, Italy). American Mineralogist, Vol. 71, pp 1426-1433.

Elena-Adriana Perseil, Philippe Blanc, Daniel Ohnenstetter (2000): As-BEARING FLUORAPATITE IN MANGANIFEROUS DEPOSITS FROM ST. MARCEL – PRABORNA, VAL D’AOSTA, ITALY, The Canadian Mineralogist, Vol. 38, pp. 101-117.

TUMIATI, S., GODARD, G. & MARTIN, S .(2005): A NEW THERMODYNAMICAL DATASET FOR Mn-RICH MINERALS:APPLICATION TO THE ECLOGITIZED OCEANIC Mn DEPOSIT OF PRABORNA,(WESTERN ALPS, ITALY), MITT.ÖSTERR.MINER.GES. 150.


Fluoropotassicrichterite
Italy
Campania, Naples Province, Somma-Vesuvius Complex, Monte Somma, Sant'Anastasia, Lagno Amendolare

Fluoropotassicrichterite FOV 20 mm© C.H.M.-Schäfer


The Somma-Vesuvius is a composite central volcano composed of an ancient stratovolcano, Mount Somma, and more recently by a cone, the Vesuvius. The age of the oldest outcrop is about 25,000 years.The latest round of activity seems to have ended with the eruption of March 1944. This eruption was the beginning of a resting phase characterized by modest signs of seismic activity and fumarole (Arno et al., 1987).
More than 230 species has been found in this area, and is one of the most interesting mineral localities in Europe. There are in principle four different mineral forming environments, each with a different mineral assemblage, and amphibole minerals can be found in all of these mineral forming environments:

I. Minerals that are found in the ejected limestone blocks of Monte Somma.
II. Pneumatolytic minerals formed in cavities of leucotephrites and conglomeratic blocks ejected by Monte Somma and Vesuvius, or coating the walls of ancient lavas.
III. Fumarolic products.
IV. Minerals that occur as rock constituents of Vesuvius and Monte Somma.

Potassium-fluor-richterite occurs as small euhedral crystals, light-grey in colour, in a skarn ejectum from a pyroclastic deposit near S. Vito, Monte Somma, Naples. It is associated with diopside and calcite. The pictured specimen has a similar appearance as the type material.

References:

Russo, M., Punzo, I., (2004): I minerali del Somma-Vesuvio. AMI (Italian Micromineralogical Association), Ed., Cremona.

A. Pelloux, (1927): The minerals of Vesuvius. American Mineralogist, Vol. 12, pp 14-21.

A. Pecerillo, (2005): Plio-quaternary volcanism in Italy. Springer Verlag.

G. Della Ventura, G.e. Parodi, A. Maras (1992): Potassium-fluor-richterite, a new amphibole from San Vito, Monte Somma, Compania, Italy. Rendiconti Lincei, Sci. Fis. Nat., Ser. 9, 3(3), 239-245.


Potassicrichterite
Italy
Campania, Naples Province, Somma-Vesuvius Complex, Monte Somma, Ercolano, San Vito, San Vito quarry

Potassicrichterite FOV 6 mm© Enrico Bonacina



Ferrorichterite
North Korea
Kangwon Province, Pyonggang-gun, Abdong (Aptong) Zr-Nb deposit

Ferrorichterite FOV 12 mm© Pavel M. Kartashov


The Apdong deposit is associated with upper Proterozoic sedimentary rocks, late Paleozoic to early Mesozoic alkali-syenites, Jurassic granites and Quaternary basalts. The ore deposit is formed by post-magmatic alkali metasomatism and occurs as irregular veins and lenses in the alkali-syenites.
Ferrorichterite segregations are found in the syenites, but not intimately associated with the ore mineralization. Associated minerals are white albite and submicroscopic lamellas of ferroferrikatophorite.

References:

Jae Ho Lee, In Joon Kim, You Dong Kim (2005): The Apdong Nb-Ta ore deposit, North Korea, Mineral Deposit Research: Meeting the Global Challenge, Chapter 9-29, pp 981-982.


Potassicrichterite
Russia
Eastern-Siberian Region , Saha Republic (Sakha Republic; Yakutia), Aldan Shield, Chara and Tokko Rivers Confluence, Murunskii Massif, Kedrovyi alkaline Massif

Potassicrichterite 8.5 cm specimen© Pavel M. Kartashov

Potassicrichterite
13cm specimen
© Weinrich Minerals, Inc.
Potassicrichterite 7.5 cm specimen© Andrey Gorshkov


The blue potassicrichterite from the Kedrovyi alkaline Massif has been marketed as "blue jade" and also “Dianite” in honour of the late Princess of Wales. The potassicrichterite occurs as microfibrous light blue, bluish green to deep blue aggregates embedded in quartz and microcline with arfvedsonite. I have not found any accounts on how much are found or the maximum dimensions of the polished slabs, but it does not appear to be very common.

The Kedrovyi alkaline Massif is one of 4 intrusive bodies of the Murun Massif. The potassic richterite are found in Sr and Ba rich carbonatites associated with the alkaline rocks. It occurs as an accessory mineral in these carbonatites together with feldspar, pyroxenes and barytocalcite(!) as the main carbonate.

The master thesis listed as literature reference for this entry can be found on the net. It gives a good overview of an exciting geological province with very special mineralogy.

References:

Ekaterina Reguir (2001): Aspects of the mineralogy of the Murun alkaline complex,Yakutia, Russia., Master thesis, Department of Geology, Lakehead University, Ontario, Canada.


Richterite
Russia
Eastern-Siberian Region, Saha Republic (Sakha Republic; Yakutia), Aldan Shield, Chara and Tokko Rivers Confluence, Murunskii Massif, Kedrovyi alkaline Massif
Richterite? 8 mm diameter sprays© Weinrich Minerals, Inc.


According to Reguir (2001), richterite is a relatively common rock forming mineral (up to 30%) in the groundmass lamprophyres associated with the Murun Massif. In these rocks, richterite is descibed as up to 3 mm large phenocrysts.

References:

Ekaterina Reguir (2001): Aspects of the mineralogy of the Murun alkaline complex,Yakutia, Russia., Master thesis, Department of Geology, Lakehead University, Ontario,Canada.


Richterite
Spain
Murcia, Jumilla, La Celia, Nuestra Señora del Carmen Mines

Fluororichterite, 0.2 mm crystal©


The Nuestra Señora del Carmen Mines is one of many sites worked for apatite in the La Celia area. The formation of apatite are linked to the intrution of ultrapotassic volcanic rocks (lamproites) 6.76 ± 0.04 million years ago. There are several such intrucions in Murcia, and richterite can be found in many of these rocks. The richterite is often K-rich and can form small well formed crystal like one pictured here.

References:

Bellido Mulas, F. Brändle Matesanz, J.L. ( ): ULTRAPOTASSIC NEOGENE VOLCANISM. Chapter 13, pp 139-145.


Richterite
Sweden
Värmland , Filipstad, Långban

Richterite FOV 10 mm© C.H.M.-Schäfer
Richterite to 9 mm individual fibres© Jorge M. Alves

Richterite 1 mm crystal©


Långban is one of the most famous mineral localities of the world, being the type locality of no less than 71 different minerals, richterite being one of them. Needless to say, the Mn oxide ores hosted by dolomitic marble and skarn have been extensively researched, and sedimentary, metasomatic reaction and exhalative sedimentary origins have all been suggested.

The oreminerals are hausmannite and braunite, which are irregularily distributed but, locally, arranged in layers giving the deposit a banded appearance. Associated skarn minerals are Mn-rich and occur along the contacts between marble and the Mn oxide mineralisation. These include manganiferous diopside, rhodonite, bustamite, manganiferous olivine and spessartine garnet, as well as manganiferous varieties of phlogopite and richterite.

Richterite is a relatively common mineral associated with rhodonite and normally found as yellowiish to brownish fibrous aggregates and small crystals as pictured. It should be noted that Sjögren(1894) describes a blue richterite, occurring as short columnar aggregates of a bluish violet/grey to a beautiful azure blue color associated with rhodonite. He publishes several analysis’ of this material, and it qualifies as richterite even today.

References:

H.J. Sjögren (1894): On the Richterite of Breihaupt and on Soda Richterite. Contributions to Swedish mineralogy part II, Bulletin of the Geological Institute of Upsala, No. 3, Vol. II.

Andrew G. Christy (2000): Långban- a short geological and mineralogical description, Skarn – www.k1q.net/skarn.

Rodney Allen, Magnus Ripa, Nils Jansson (2008): Palaeoproterozoic volcanic- and limestone hosted Zn-Pb-Ag-(Cu-Au) massive sulphide deposits and Fe oxide deposits in Bergslagen, Sweden, 33 IGC excursion, No. 12, August 14-20, 2008.



Olav Revheim, March 2012

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Edited 26 time(s). Last edit at 08/21/2014 05:52PM by Becky Coulson.
avatar Re: Richterite series
March 19, 2012 08:27PM
Okav,
Now that's a labor of love. Do you have anything planned for your next project?

Rock Currier
Crystals not pistols.
Re: Richterite series
March 20, 2012 09:50AM
    
Thank you Rock.

As for upcoming projects, there is still a lot of work left on the amphiboles. My plan ahead is to:
1- continue with the Winchite series
2- the katophorite-series
3- update the amphibole group main article with the subgroup 3, sodic-calcic amphiboles
4- write articles on the varieous subgroup 4-sodic amphiboles.
and so on.

Inbetween there is still work left on the corundum articles, so I think that I will keep myself occupied for a while still. smiling smiley

All in all I think the Best Minerals project is moving along nicely, although it would be nice with a few more regular contributors.

Olav
avatar Re: Richterite series
March 20, 2012 10:10AM
Yes, more regular contributors would be nice. We may have a new one joining us soon. We will see if his trial articles work out.
Rock

Rock Currier
Crystals not pistols.
Re: Richterite series
March 20, 2012 01:47PM
Brilliant, Olav, I have often wondered what the white double ended crystal was with a specimen of hanksite that I have, it comes from Afghanistan, and the crystal is 4 cm long and completely clear.

Spencer.
Re: Richterite series
March 20, 2012 02:45PM
Thanks again, Olav. I too, found a ''something-in-quartz'' in the RR ballast that looks very much like the photo from Italy,the one sized 6cm. That will do for now,( and probably for a very long time!) as an approximate ID.
Also, not a critique, but should the formula for Fluororichterite have "Na" where the "K" is? Otherwise it is the same as one other formula. I'm looking at 'Fleischer's Glossary'...
I know, "Picky, picky!" lol

Mike
Re: Richterite series
March 20, 2012 06:54PM
    
Thank you very much Spencer and Mike. I really appreciate your input and comments.smileys with beer

The K in the fluorrichterite formula is a classic cut and paste error on my behalf. Thank you for spotting. I do that all the time, and I appreciate that you make me aware of them. Not at all picky.

Spencer,

From what I understand, Hanksite is an evaporite mineral that are formed at a "near surface" pressure and temperature. I am not sure that any Hanksite that may have been originally present in the Koksha evaporites would survive the amphibolite facies pressure and temperature required to form richterite: I doubt that richterite and hanksite can occur together because of this, but others will know more on the subject than I do smiling smiley

Mike,

Potassicrichterite is a very rare mineral, and any light coloured hairlike amphibole is much more likely to be in the actinolite/tremolite series, varitey byssolite, see Byssolite gallery, especially if associated with quartz..

best regards

Olav
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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.
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