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Tremolite

Posted by Olav Revheim  
Tremolite
October 03, 2010 11:27AM
no    
First draft



Click here to view Best Minerals T , and here for Best Minerals A to Z and here for Fast Navigation for finished first draft 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?


Fluorotremolite
☐Ca2Mg5Si8O22F2

Parvomanganotremolite
☐(CaMn2+)Mg5Si8O22F2

Tremolite
☐Ca2Mg5Si8O22(OH)2

Tremolite 2.7 cm © Rob Lavinsky
Tremolite & Uvite 8cm wide©
.
Tremolite 2.8 cm tall© vasco trancoso

Tremolite is a mineral in the Amphibole group, see Amphibole Group main article for an overview of the group. Tremoliteforms a continuous series with actinolite, see Actinolite

Tremolite was first described as a new species in the late 18th century. The name of the species is derived from the Val Tremola, a valley in the canton Tessin. However, tremolite has never been found in that valley. Studies of the early literature and of the specimens preserved in old collections has clearly shown that the true type locality is the Triassic dolomite of Campolungo, Tessin (Stalder et al., 1998), an area also famous for the large corundum crystals first found there in the mid-19th century (e.g. Rovetti et al., 1994).

In the IMA nomenclature of amphiboles tremolite forms part of the tremolite–actinolite–ferro-actinolite series: Whereas usually the dividing line between two species in a continuous solid solution series is set at the 50% point, tremolite occupies only a narrow range. It is defined as having an Mg/ (Mg+Fe2+) ratio ≥ 0.9; actinolite has a ratio of 0.5–0.9 and ferro-actinolite has a ratio of less than 0.5. These limits are designed to satisfy the strong desire, expressed especially (but not solely) by metamorphic petrologists, to retain the distinction of green actinolite from colorless tremolite. Another reason is that tremolite is an important mineral in the definition of metamorphic zones, and the diagnostic color distinction so useful in the field is entrenched in the literature; a change in the definition of the mineral would have complicated the application of important previously published studies.

Tremolite is, like all the other amphibole group minerals, difficult to distinguish from some of the other minerals in the group without chemical and structural analysis. I have limited the minerals and locations described in this article to the entries in the database supported by proper analysis . This has left out several good locations where the amphibole is tentatively identified as tremolite, but I think the value of the article is higher if the information contained inside is reasonably correct. The good tremolite locations where I have not been able to positively ID are presented in the amphibole group article.
Since all amphiboles have similar physical properties, such as crystal habits, cleavage, hardness, specific gravity and so on, we often turn to color to identify the individual minerals in the amphibolites group, and more often than not, whitish or light colored amphiboles tends to be labeled tremolite. This is not a recommended practice, as many amphiboles (such as edenite, cummingtonite and antophyllite) can be light colored, and tremolite can be white, grayish, brown, yellow, green and lilac. Color is therefore not necessarily a reliable means of identification.

It is difficult to discuss any amphibole without establishing the chemical relationship to the other amphiboles. Tremolite fits nicely into the general amphibole formula of AB2C5T8O22(O,OH,F,Cl)2, having an empty A position, Ca in the B position and Mg in the C position, generating the formula Ca2Mg5Si8O22(OH)2.
In slightly different chemical environments other amphiboles can be formed rather than tremolite.
- Fe enriched environment- Fe enters the C position and the amphibole becomes actinolite ( In order to be tremolite, Mg must occupy more than 90% of the C position sites, actinolite from 10-50% Fe in the C site and ferroactinolite > 50% Fe in the C site.)
- Al enriched environment- Al enters the C and T positions and the amphibole becomes magnesiohornblende
- Na enriched environment – Na enters the A position and Al the T position and the amphibole becomes edenite
- Mg enriched environment – Mg enters the B position and the amphibole becomes cummingtonite or anthophyllite.

Consequently, in order for the amphibole to be tremolite, the geological environment must be suitable. There must be sufficient temperature and pressure to form an amphibole mineral, combined with a chemistry with a sufficient content of Ca, Mg and Si, and not too much Al, Fe og Mg. The ideal environment for tremolite formations are metamorphosed sedimentary rocks containing dolomite and quartz, and not too much of the other stuff. This combination is relatively common in greenschist-facies to amphibolite-facies calc-silicate, skarn and in some low-grade ultrabasic rocks. In any other rock, one should be even more cautious in naming an amphibole tremolite than in these rocks.

Tremolite is not a favorite amongst collectors; it is to often a dull whitish, grey color with intermingled crystal fibers without terminations. Often more interesting minerals from the same location are the focus is for collectors, leaving fibrous tremolite as the matrix on a specimen. This is definitely the case both for Outokumpu, Finland and Merelani Hills, Tanzania where uvarovite and tanzanite respectively are the favored takeaway from the location. There are nevertheless some quite stunning locations out there, in particular the green, gemmy crystals from Tanzania and the pink/lilac crystals from the East Coast of the USA. The crystal groups from Haliburton County are also nice. Individual terminated crystals can reach several centimeters from all of these locations. Good, well crystallized and nicely colored specimen may well reach prices exceeding 1000 USD, and a display with a green gemmy crystal from Tanzania, next to a large lilac Lawrence County tremolite var. hexagonite and a white terminated Canadian crystal should enable slightly more attention to this mineral than it receives today.

In rare cases, gemmy crystals from Tanzania and Canada have been faceted, but tremolite will probably never become a popular gemstone. It is too rare in gem quality, not hard enough and I suspect that the perfect cleavage has caused some grief for those trying to make tremolite gems.

Nephrite jade is a common name for tight massive amphibole that is extensively used in preparing jewelry and art objects. Tremolite may well form nephrite and provide very lightly colored jade. This article does not discuss tremolite-nephrite as I think jade deserves an article entry in its own right.

Fibrous tremolite-asbestos have previously been mined and has been responsible for numerous deaths amongst miners and people working with asbestos products. These products are thankfully banned now. Some places, like nearby Kabul, Afghanistan the soil contains so much naturally occurring asbestos fibers that people may get asbestos related diseases.


Tremolite
Afghanistan
Badakhshan Prov

Tremolite, main crystal 1,5 cm tall© Fabre Minerals


The Badakhshan province is Afghanistan's northernmost province, and also one of the largest. It covers and area of approximatel 44,000 sq.km, roughly equal to that of Switzerland and twice the size of New Jersey. The mountin ranges Hindu Kush and Pamir lies in the heart of the province, and the highest peak of Hindu Kush, the Tirish Mir reaches 7,708m above sea level. The Badakhstan province hosts one of the most exiting and exotic mineral locations in the world, namely the Sar-e-Sang quarries where lapiz lasuli has been retieved for several thousand years.

I have found very few references to tremolite from Bandakhshan. This picture of tremolite is one of the very few, and tremolite is not listed in the Mindat database at all from Afghanistan. This does not mean that tremolite cannot be found there. The geological setting with lime bearing sediments metamorphosed to the amphibolite facies surely indicates the oppposite. The lack of recorded tremolite locations in Bandakshan I think, is more due to the limited value of the mineral, and that great collector specimens has not hit the international market yet.

This leaves a few questions for this specimen. The geology of the area clearly indicates that tremolite should be present, but the lack of documentation indicates that specimens on the quality of the pictured specimen is not readily available. I suspect that this pictured specimen may be winchite from the Koksha valley (see [www.mindat.org]), rather than tremolite.
Can anyone confirm this specimen as tremolite?.


Tremolite
Canada
Ontario, Haliburton Co., Cardiff Township, Dyno Turn Tremolite

Tremolite 9 cm wide© Jay Vonderhey


Speaking in geological terms, Haliburton County lies in the "central metasedimentary belt" in the Grenville series of rocks. The tremolite here is formed in metamorphosed Mg-bearing marbles- dolomite marbles. Although many dolomitic marbles has originated from dolomitic sediments, this does not seem to be the case here, where it is believed that the Mg influx has originated from igneous intrusions. The silica required to form tremolite seems to be a combination of residue silica from the sediments, combined with influx from the igneous rocks. Numerous mineral locations are found in skarn or calc-silicate rocks on the border between the igneous and metasedimentary rocks, and it seems as if tremolite are found both in these skarn zones and embedded in the marble itself.

This occurance is a road cut, and it seems to be a contact type occurance where white tremolite are found in the contact zone between marble and another rock. Tremolite seems abundant at the locality.

Listed Reference for locality: Schroetter, Ralph. The Bancroft & Area Mineral Collectors Guide. Dyno Turn Tremolite. pg148, full edition.


Tremolite
Canada
Ontario, Haliburton Co., Glamorgan Township, mo Tremolite occurrence

Tremolite & Diopside ~7cm wide © MJB, 2009


This is a largely unexplored, but apparently widespread occurrance of large clots of diopside and tremolite in marble, with some quartz. Tremolite occurs as white, gray, light blue/green, and deep smoky brown crystals to several inches, in coarse calcite and massive quartz. Colourless and brown crystals have been found in gem quality but most are fractured.
Reference: Microprobe analysis by Glen Poirier at the Canadian Museum of Nature


Tremolite
Canada
Ontario, Haliburton Co., Harcourt

Tremolite, 3.2cm© 2001 John H. Betts


Leach (1964, p.10) mentions green gemmy material from Harcourt, in the Bancroft district, which would yield cats-eye cabs or tiny facetted stones. Reference: ontariominerals.com


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

Tremolite 6.6 cm tall© Weinrich Minerals
,

Waite(1944) mentions a deep blue marquis brilliant 0.70 ct stone from here: reference: ontariominerals.com


Tremolite
China
Hebei Province, Baoding Prefecture

Tremolite 6 cm tall© Safaa Yu
,

The location for this specimen, the Baoding Prefecture covers an area of 22,159 km2, so pinpointing the location to a level of details as for the Canadian localities above is not possible. Also realizing that the Baoding area mainly consists of flat, agricultural plains, opens for a suspicion that the pictured specimen may be from the Taihang mountains further west. The rocks in the Hebei province ( covering a mere 187,700 km2) is of mainly metamorphic origin supporting the existence of tremolite. I would however like some more details on the origin and ID pf the specimen to include it in the final article due to the many amphibole minerals that may look similar to the pictured specimen.


Tremolite
Finland
Itä-Suomen Lääni, Outokumpu Cu-Co-Zn-Ni-Ag-Au ore field

Tremolite in Calcite 1cm crystal
,

The Outokumpu ore lies along the western margin of a serpentinite body. Both the ore and the serpentininte body is enveloped by a carbonate/tremolite skarn. The greene chromium rich tremolite is found together with calcite, sulphides, uvarovite and chrome minerals in some areas where the skarn is in direct contact with the ore body. The rock is matamorphosed to middle amphibolite facies.


Tremolite
Kenya
Umba Valley region

4cm Tremolite xl in Calcite© 2002 John H. Betts
,

It seems as if green tremolite coloured by vanadium is found associated with the grossular variety tsavorite in the gem mines in the area. The geological environment seems similar to the Merelani hills in Tanzania, where tremolite is found in calc-silicate rocks between the dolomittic marbles and graphite bearing gneiss.


Tremolite
Madagascar
Antananarivo Province, Vakinankaratra Region, Antsirabé 2 District, Mt Ibity (Mt Bity),Ibity Commune, Ibity massif

Tremolite 2,2 cm crystal© Rob Lavinsky
,

Tremolite from Ibity has been known for a long time. The mineral identification is confirmed through testing published at Rruff.info and in other publications. Tremolite is normally found as green euhedral crystals up to a couple of cm long. The crystals is often of good quality, sometimes transparent and often without inclusions. The green color is probably due to a small iron (~2,0%) content, and consequently border line to actinolite.


Tremolite
Madagascar
Tuléar (Toliara) Province, Anosy (Fort Dauphin) Region, Taolañaro (Fort Dauphin) District, Ranomafana-South Commune

Tremolite 8 cm wide after wollastonite© Arliguie M
,


Tremolite
Norway
Nordland, Rana, Storakersvatn

Tremolite 7 cm wide after diopside© Martins da Pedra
,

Tremolite was described from several locations in Nordland by Vogt already in 1897. The tremolite is found in dolomittic marbles in caledonic rocks. Storakersvatn is the most renown location in the area, and especially the tremolite pseudomorphs after diopside can be quite attractive. These pseudomorphs is quite common in sizes exceeding 10 cm. Also regular whiteish fans of fibrous tremolite are known from road cuts along the gravel road alongside the lake. The individual fibres can be quite long. The host rock at Storakersvatn seems to be calcite cemented dolomittic sandstone.


Tremolite
Switzerland
Ticino (Tessin), Leventina, Piumogna Valley, Campolungo

Tremolite 22 cm wide© luigi chiappino
,

Tremolite is named after the Tremola Valley, not far from the Campolungo site, despite the fact that tremolite does not occure in the Tremola Valley, and due to the rock forming conditions there cannot exist either. All the earliest tremolite specimens offered to museums and collections after its discovery in 1795 came from Campolungo. The quote below shed light on the events leading up to the misunderstandings surronding the type location of tremolite:

"When, about twenty years ago, tremolite was found in the high, almost inaccessible rock cliffs of Campo Longo, opposite to the Gotthardt pass, such a fossil [= mineral] was little known from other localities. People were delighted about and amazed by the beauty of the new product, and the demand it triggered was high. This raised the wish of the discoverer, probably a farmer in Airolo or in Fontana, to remain in the exclusive possession of its sales and when one asked the specimen dealer Vizard in Berne through whom at that time the fossils from the Gotthardt were made popular where the new fossil came from, he would mention the Val Tremola as its birthplace. Thus the name tremolite was adopted, irrespective of the fact that no trace of the mineral exists in Val Tremola. However, the regions of the Gotthardt were soon explored more thoroughly; mineralogists scaled the cliffs of Campo Longo themselves; and tremolite was also found in other European localities."
Von Buch L. (1809): Der Gesellschaft naturforschender Freunde zu Berlin Magazin für die neuesten Entdeckungen in der gesammten Naturkunde, 3, p. 172

The above quote are taken from "The Early History of Tremolite" by Philippe Roth

Tremolite form the type locality origins from a silica rich triassic dolomite on the border between dolomite and quartz. This border zone rarely exceeds a thickness of 4 cm, but can be considerable larger parallell to the quartz. Cabinet sized specimens can consequently be found. Tremolite occurs both as crystal aggregates and single crystals.

Tremolite from Campolungo has, due to it's abundance in various museum collections, been used in numerous studies on amphiboles and the geological settings in which they occure.


Tremolite
Tanzania
Arusha Region, Lelatema Mts, Merelani Hills (Mererani)

Tremolite 5,7 cm© Weinrich
Tremolite 2.8 cm tall© vasco trancoso

The famous tanzanite mines of Merelani is also one of the world’s finest tremolite occurrences Although the location has been known by science since early in the 1960-ties, tremolite was not found here until 2005 when vanadium-rich (and probably chromium-rich) tremolite in single crystals to 2.8 cm, and jumbled groups of splintery tremolite crystals of a pearl-white to apple-green color were available at the 2006 Tucson Show. New finds in 2007 and onwards has led to a small and unsteady supply of new material, and several dealers offered crystals up to 3 cm in 2009.

Finely acicular crystals on tanzanite and heulandite have also been identified. The tremolite crystals all thought to be from Block D (see explanation below). The pale green Merelani tremolite crystals contain 0.32 weight percent V2O3 and probably trace amounts of Cr2O3 , which are thought to be the coloring agents. The deeper grass-green crystals probably contain moreCr2O3 . The tremolite shows a weak orange fluorescence under longwave ultraviolet light, and a moderate greenish yellow fluorescence under shortwave ultraviolet light.

The Merelani's tanzanite mines lie within 2 km wide by 8 km long field, first discovered by prospectors searching the steppe for anything of value. Small scale mining started in the 1960-ties, and has not been run as a large scale operation before the early 1990-ties. Mining started as a haphazard collection of small diggings and open pits in alluvium and bedrock but has expanded continuously into several major workings and many hundreds of small operations.

The Merelani mine today consists of four major parcels referred to as Block A, Block B, Block C and Block D, each exploiting veins that go successively deeper (from A to D). There are also several extensions, and the Machakecho workings, just to the west, where small-scale miners have exploited an alluvial deposit of tanzanite. Block A does not produce much, and today the majority of the production comes from block C, where a modern , hi-tech operation are run, producing between 1.5 and 2 million carats of tanzanite in 2009. Most collector-quality uncut crystals reaching the market are from the "native blocks" (Block B and Block D) where mining is conducted by hand, in a not so modern and highly dangerous operation.

The tremolite (and tanzanite) is found in metasedimentary rocks with a complex history of repeated metamorphic events. What originally started out as Al-rich calcareous, arenaceous and pelitic sediments was first metamorphosed to granulite facies at temperatures between 520 and 730 deg C and 7,7 to 9,1 Kbars, but later retrograde actions has formed kyanite-almandine rocks with beds of dolomitic and siliceous crystalline limestone. Bands of graphite gneiss, quartzo-feldspathic gneiss and kyanite gneiss are intercalated with the limestone. The gem material are formed by later crystallization in faults originated in the rocks, and vanadium and chromium leached from the metasediments has been incorporated in the minerals found in these faults, giving the strong and unusual color to the minerals. This recrystallization phase took place during the Mozambique Orogeny around 600 million years ago,

Literature:
Petrology and lithogeochemistry of the mineralized tanzanite-grossular bearings rocks in the Merelani-Lelatema area, northeastern Tanzania, Tanzania Journal of Science Vol 29 (2003) EP Malisa

The Merelani tanzanite mines: Lelatema Mountains, Arusha Region, Tanzania, The Mineralogical Record (sept 2009), Wilson, Wendell E.

Yellowish green diopside and tremolite from Merelani, Tanzania, Eric A. Fritz, Brendan M. Laurs, Robert T. Downs, and Gelu Costin


Tremolite
USA
Connecticut, Litchfield Co, Canaan, Falls Village, Canaan Lime Quarry (Redwing Quarry)

Tremolite in calcite 5 cm spray© 2000 John H. Betts
,


Tremolite
USA
New Jersey, Sussex Co., Franklin Mining District, Franklin,Franklin Quarry (Moses Bigelow Quarry; Farber Quarry)

Tremolite 3.5 cm

The Franklin mining district is host for 353 valid mineral species, and is the type locality of 68 of those. Several amphibole minerals are amongst these, tremolite therefore being one of many similar minerals, so label with caution.

Tremolite is a common accessory mineral in the Franklin Marble, which is a coarsely grained calcite marble, which is locally local dolomitic. Tremolite is rarely found in the calcium silicate units of the orebody ( actinolite is more common near the orebodies, in particular near franklinite).

Tremolite occurs as euhedral crystals in much of the Franklin Marble. The crystals may occationally reach 10 cm and more in length, and are associated with graphite, chondrodite, calcite, arsenopyrite, phlogopite, chlorite, and other species. The Franklin tremolite is colorless to white or gray, with vitreous luster. Analysed samples shows impurities of Mn,Zn and Fe, with some species intermediate in composition between actinolite (which is also present) and tremolite.

From time to time also pseudomorphs of diopside after tremolite, in which brightly-fluorescent diopside has replaced bladed crystals of tremolite can be found

Fibrous tremolite has also been identified on on slickensides with zincite , carbonates and serpentine



Fluortremolite
USA
New York, Orange Co., Pine Island, Atlas quarry

"Fluorotremolite (fig. 8) from the Atlas quarry occurs in long prismatic to acicular, transparent, colorless to pale gray crystals to 4 cm, in parallel growth with fluoro-edenite, or isolated in marble. Inclusions of graphite flakes oriented along the elongation of the crystals are common. The mineral fluoresces pale yellow with a greenish tint in longwave and strong yellow with greenish tints in shortwave ultraviolet radiation."

Marian Lupulescu (2008): Amphibole Group Minerals from New York State. Rocks & Minerals, Volum,e 83 May/June.



Tremolite
USA
New York, St Lawrence Co., Gouverneur, Reese Farm (Dale Bush Farm; Jones Farm)

Tremolite ~11cm wide©
Tremolite & Uvite 8cm wide©

The Reese Farm are more known for its tourmaline specimens, but excellent tremolite specimens and combo specimens have also been, and still can be found.

The Lawrence County of New York in the USA hosts a number of tremolite occurrences, Mindat lists 29 locations, and there are probably many more in the metasedimentary and metasomatic precambriam rocks formed in the Grenville orogony. The area is one of the classic sources of mineral specimens, shown by the following quote:

“No introduction to the minerals of the western Adirondack region in upper New York State need be given to any one interested in mineralogy. Good crystals from its many localities adorn nearly all mineral collections and most of the easily obtainable show specimens were taken long ago. There is still a great deal left, however, which will repay a trip into the region.”

The quote is taken from “The Minerals of St. Lawrence, Jefferson and Lewis Counties, New York.” By W.M.Agar, Princton University, 1921.

Unlike many other places, the tremolite found here is of particular interest for collectors. This is more than anything due to the manganese bearing variety hexagonite, showing a beautiful lavender color, thus automatically becoming more attractive. Hexagonite was at first interpreted as a mineral with hexagonal crystals, related to beryl, but this first assumption was firmly corrected by George A. Koexig Ph.D in a short paper published at the Philadelphia Academic Society in 1876:

“The appearance of the mineral is altogether novel and striking; the fine light amethystine color, and a peculiar lustre, together with the aggregative entwining of the crystals, renders it very attractive to the eye. My doubts as to the accuracy of Mr. Goldsmith's determination being roused, I resolved to examine the mineral myself, having
been furnished with plentiful material, through Mr. Clarence C.Bement's kindness, who was the first in this city to obtain it.”

As the title “Hexagonite, Goldsmith, a variety of tremolite” suggests, Dr Koexig it nailed it. He supports his conclusions by careful crystal measurements and chemical analysis, even to the detail where he attributes the pale lilac color to the small Mn Content.

The tremolite, together with other minerals formed by metamorphic reactions between the marble and quartzite. It is believed that some of the tremolite have later been altered to talc, anthofyllite and serpentine. This retrograde metamorphosis has been extensive to the level where talc has been and still is mined.

The colourless and white tremolite are predominantly found directly in the marble and large subhedral crystals to more than 50cm long and 15 cm thick can be found. Terminated, well formed crystals rarely exceeds 10cm.
The hexagonite variety is found in nearly mono-mineralic zones between the massive talc ore and
hanging wall dolomite, and the individual crystals are normally less than 1cm, but individual crystals exceeding 10 cm are known.


Tremolite
USA
New York, St Lawrence Co., West Pierrepont, Selleck Road Locality (Selleck Road tremolite locality)

Tremolite 4.5 cm tall© 2001 John H. Betts
,


Tremolite
USA
New York, St Lawrence Co., Balmat-Edwards Zinc District

Tremolite 10.8 cm crystal© Rob Lavinsky
,


Tremolite
USA
New York, St Lawrence Co., Fowler

Tremolite 2.7 cm © Rob Lavinsky



Tremolite
USA
New York, St Lawrence Co., Fowler, Gouverneur Mine

Tremolite 11.45cm wide© Jasun McAvoy
Tremolite, 2cm xl.© Martins da Pedra


Tremolite 6.6cm wide© Jasun McAvoy
Tremolite 3.62cm tall© Jasun McAvoy




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



Edited 36 time(s). Last edit at 03/26/2012 09:38AM by Olav Revheim.
avatar Re: Tremolite
October 04, 2010 12:20AM
Olav,
Ive made a few tweaks, mostly to the images. You may find that when you use the little tourmaline icon to insert the code string for the insertion of images into the articles, that you may want to change the default standard of 600 pixels to 400 pixels. This will allow you to place two images across in the articles and leave a little room left over for tweaking the images. It is better to list each locality separately rather than lump them under "various localities" although this can seem a bit tedious at times. In various deposits that are accessed by the several shafts we may be able to get away with this, though some mines in the same deposit can produce distinctive minerals and here we will probably want to break that locality out as well from the rest. Like the Kelly mine, the Graphic Waldo etc etc.

Another trick that I have found useful especially in cases where you want to show two or more images of specimens from that locality is to create your own code string, one that looks like this:

[ pic id=XXXX width=400 float=left][/pic]

You can copy this to some sort of word processing document like word pad that you can quickly access and copy this code string for insertion into your articles when ever you need it. Note that there is an extra space after the first bracket that you will need to delete.

If you want to show ten images for a particular locality you can just copy the above code string and then copy it five times directly into the article and then just replace the XXXXs with the image numbers you want to insert into the article. It can save you a lot of time.

Rock Currier
Crystals not pistols.
Re: Tremolite
November 23, 2010 09:05PM
no    
First draft version of the Best minerals, Tremolite article is complete.

I would love someone familiar with the Canadian and US locations to step up and fill in more specific details on the different locations and the appearance of the tremolite at these locations. Given the large number of locations in these areas, there are probably additional locations that should be added.

Someone must now more on the chrome-tremolite from Outokumpo, Finland also. Any additional information will be helpful.

Any suggestions, corrections and/or information will be highly appreciated.

Olav
avatar Re: Tremolite
November 23, 2010 10:05PM
Olav,
Excellent job. It is frustrating when we get right down to it about how little we know about some of the things we write about, especially about all the localities we have never visited or collected at, so ultimately we are left hoping that others that know more about them will come along and help us with information. However you have added more information than most. You have some clean up to do to bring the format in line with the rest of the articles. and when I get a chance, Ill go in and do a bunch of it if you don't have the time. Its just rearranging the pictures text and line spacing a little to create the "data blocks" that I hope will make it easier to translate the best minerals project into a good database format in the future. Again, a good effort and a solid contribution to Mindat and Best Minerals.

Rock Currier
Crystals not pistols.
avatar Re: Tremolite
November 25, 2010 11:23AM
nl    
Great job done Olav!
avatar Re: Tremolite
November 26, 2010 08:30AM
Olav,
I have gone through the Tremolite article and did what I call a clean up which was mostly adjusting the format a little, tweaking the pictures and at the bottom I added some pictures for the Gouverneur Mine, in New York.

Some time ago one of our mindat regulars endeared himself to all the people working on this project by calling it an organisational and editorial quagmire, and undoubtedly he still feels that way. So I do what I can to keep the format more or less the same in all the articles that make the first draft finished stage.

Our format is more of less fixed, but still not yet cast in stone and one of the things you did in this article points one of the things that has been troubling me and I am still not sure how we should ultimately handle it. In a couple of places where tremolite is found in many related localities in a region like Canada and New York, you prefaced those places with a section of general comments which is good and necessary. I have been in the habit placing these general comments under the first locality in those series of localities rather than at the top of those localities. I have moved your general comments into the first localities or those regions to let you see how it looks. I am not at all sure that this is the best place for them and perhaps they should be placed ahead of the locality swarms. Take a look at the way I have done it and if you think it is better ahead of the locality swarm, put it back up there and I will leave it alone and will in the future let each author decide which is best. If Harjo and the other authors feel these comments are best at the head of locality swarms, I too will follow that lead.

In many places in your text you placed in bold text words like: I have not found much information on the individual locations, and any information on maximum crystal size and general information on the localities will be much appreciated. You will notice that I have removed those. When I started I placed wording similar to that in my own articles, but after while realized that the articles were so peppered with those kinds of comments to appear almost comical and for that reason I removed those comments and made sure at the top of each article was the statement we currently have requesting help and information on the localities where we didn't have any information.

I am gratified that you have picked up the trick of stacking two images to the right of one tall one. This trick is especially helpful when you have 15 or twenty images for a locality that you need to arrange and make pretty.

So take a look at what I have done and change back the general regional comments you made to their original position if you wish, and I will consider the first draft on this article done. When it is done, you should remove the under construction note at the top of the article and place it in the first draft finished fast navigation list. If you need help with this, just rattle my cage.

Rock Currier
Crystals not pistols.



Edited 1 time(s). Last edit at 11/30/2010 12:35AM by Rock Currier.
Re: Tremolite
November 29, 2010 01:24PM
no    
Rock,

Thanks for your patience with my lay-outs or lack of such. :). I really appreciate that you find the time to make corrections to align the work I do with the others.

I agree in taking away the bold " more information wanted" texts, and also your efforts in keeping the articles streamlined in design. I must admit that I am not always good at following instructions and guidelines.

With regards to the "general area" comment, i am ready to follow any consensus on the matter and I see the benefit in having a consistant look and feel for all locations, independant on their geographical or geological proximity. Personally, I prefer to place general comments under a district heading rather than under the first location in an area as what is generally true for an area might not be as true for the locality. It is not a big issue for me either way.

I have placed a link in the fast navigation list.

Olav
avatar Re: Tremolite
November 29, 2010 07:31PM
Olav,
The Tremolite article looks good. If you like the general comments for an area of geologically similar localities to proceed the group, I say go ahead and put them back ahead of the groups. However, just before them you should put in bold

Tremolite
the country
and the general locality

When it comes to inserting the data blocks that we are creating into a database structure, we will have to make some sort of provision for the intriductry remarks for those locality groups that have introductory remarks.

Rock Currier
Crystals not pistols.
avatar Re: Tremolite
November 29, 2010 09:31PM
nl    
Regarding the general comments on a string of similar localities in a confined geological area with very similar occurrences of similar crystals: I think it works quite good if we take the area as locality, followed by photos from specimens from the different localities within the specified area and have that followed by a general description of the area wherein the different localities and the specimens from those are mentioned in more detail.
I don't really see a point in having, for instance, three separate locality entries, with three times a very similar comment, for three quarries that are situated a couple of km from each other, are in the same geological area, have the same paragenesis and deliver the same quality and alike specimens.
Another possibility is to make locality captions for each locality in that area followed by photos from that locality without text between the closely related localities but only a general comment wherein the separate localities are mentioned after the last locality of the string.
Another thing I tried in one of my first articles (Calcite Belgium) is for every geological era/area a separate preface describing geology, followed by the individual localities with a comment under the photos for each locality. This works very nicely when the article is about a mineral from one specific country but of course it doesn't work when the article is about a mineral species worldwide.
avatar Re: Tremolite
November 29, 2010 10:03PM
Harjo,
I think we must still separate the localities as much as we can. Two examples of why this should be come to mine. Take the Deccan Traps, in India and the Watchung traps on New Jersey. Swarms of localities all in pretty much the same geological setting. Collectors collect them pretty much by the Individual quarry and even though they are often not far apart. The mineralization is often distinctive enough to separate them by looking at the specimens and often there are historical timeline differences. Also, mindat lists them as separate localities and if we are going to fit the localities into a database structure I think we should stay as close to mindat's current structure as possible. There may be a few instances where we can group them as you suggest, but with the lead in comments for the locality swarm we would not have to repeat a lot of the same information for each locality, just concentrate on talking about what differences there are and what makes them distinctive. There are are a few instances where the area as a locality might work and in fact be desirable, but I think whether they are separated or not would depend on how they are treated by collectors and museums. Should the Parker Shaft be considered as a separate locality from Franklin even though it is basically the same mine? There are collectors who specialize in specimens from there so I think it should be a separate locality. The Borates from Boron California. There are a number of mines that have exploited the deposit, but in fact 99.9%+ of the specimens from there are from the open pit mine. Perhaps your concept might work here. But there were some specimens of Gerstlyite that came from the Old Western mine which was operated by a separate company and we might want to break that away from the open pit where almost the rest of the specimens came from. There are the borax crystals and the clam shell ulexites that came from the underground workings from the Baker mine and not the open pit, so even here we may wish to give two or three localities for Boron rather than just one.

Rock Currier
Crystals not pistols.



Edited 1 time(s). Last edit at 11/30/2010 12:40AM by Rock Currier.
avatar Re: Tremolite
November 29, 2010 11:09PM
nl    
Yes Rock, I agree. In cases like the ones you mention individual localities of a string should get their own entry and comment.
In those cases the string of locality entries with their own comments can be followed by a general comment, what do you think about that?
Mark Germine
Tremolite From Afganisthan
May 24, 2012 07:45PM
Regading the Afghan tremolite. It looks like a monoclinic amphibole, but I can tell for sure using electron microscopy where I can determine its structure and composition. All I would need is a pea-sized sample and I would send results and data. I am Dr. Mark Germine and my e-mail is
drmgermine@gmail.com. Let me know by email what you would like to do and I will gladly get the data for you, as my mineralogical work is primarily with the monoclinic amphiboles.

Sincerely,

Mark Germine
Re: Tremolite
May 25, 2012 08:07AM
no    
Mark,

Thank you very much for you offer to positively ID this specimen. The only problem is that the only thing we have is the 4 year old photograph uploaded by Fabre Minerals. It is not possible to tell the current whereabouts of the specimen, unless of course the current owner reads this thread and is sufficiently intrigued by the possibility that his "tremolite" may be a more exotic amphibole and contact you.

I would however appreciate very much if you had the time and opportunity to review some of the amphibole articles that are posted in the "best minerals" section of the Mindat database. With your experience from working with amphiboles I am sure you will be able to find errors and omittions in these articles that should be corrected. A list of the "first draft" status articles with links to the individual articles can be found here[/url

Best regards

Olav Revheim
avatar Re: Tremolite
May 25, 2012 09:26AM
Olav,
You could contact Jordi Fabre and ask about the specimen. He might even have some of the stuff laying around or be able to put you in touch with the source. I think Jordi would like to help out with this kind of investigation if he can. I know I would.

Rock Currier
Crystals not pistols.
Re: Tremolite
May 25, 2012 12:29PM
no    
Rock,

Tanks for the tip. I will do as you suggested when I revisit this article smiling smiley

Olav
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