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Rhodochrosite

Posted by Rock Currier  
avatar Rhodochrosite
January 03, 2009 05:52AM
Click here to view Best Minerals R and here for Best Minerals A to Z and here for Fast Navigation of completed 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?


RhodochrositeMn2+CO3 trigonal

Rhodochrosite, Fluorite & Quartz, Sweet Home Mine, Colorado, USA 11.5cm across



Rhodochrosite has been around as a mineral since the late 1700s when it was recognized as being a mineral with manganese and oxygen and as a manganese carbonate since the 1800s. The name rhodochrosite dates from the early 1800s. The Germans called it rosenspath.1 Early texts like Dana 6th say that distinct crystals are not common which seems to be at odds with the plentiful images of beautiful rhodochrosite crystals that seem to be everywhere when you go looking for pictures of rhodochrosite. Rhodochrosite is not always red, but quite often pink and even brown and in colors aproaching white. It is one of the rhombohedral carbonates but not all rhodochrosite is pure end member manganese carbonate. There is a complete series where Mn2+Fe2+, Ca and probably Mg can substitute for each other in various degrees. 2, 3 Those rhodochrosites that contain mostly manganese in their structure, especially the nice red, fairly transparent ones are amazing impervious to reacting with concentrated hydrochloric acid. To see any reaction at all with even concentrated hydrochloric acid, you must grind it to a very fine powder, and even then it reacts slowly. When I last checked, Mindat has something over 1100 images of rhodochrosite from a little more than forty localitys that produce respectable specimens. It is found in hydrothermal veins that were formed in low to moderate-temperature ranges, metamorphic deposits and is common in carbonatites, authigenic and secondary sediments, but uncommon in granite pegmatites.3 Fine red crystals of rhodochrosite are highly sought after by collectors and individual specimens from the Sweet Home Mine in Colorado have sold for more than a million dollars and fine miniature size specimens for many tens of thousands.
1. A System of Mineralogy, Dana, 6th edition1892, p.279. 2. Dana's System of Mineralogy, Palache, Berman & Frondell, Vol 2. p.171. 3. Handbook of Mineralogy, Anthony, Bideaux, Blada & Nichols, Vol. V, p.590. 3. 1. Mineralogical Record, Sweet Home Mine Issue, July-August, 1998, Vol. 29 No. 4. p.123-127.



RhodochrositeArgentinaCatamarca, Andalgalá, Capillitas Mine

Rhodochrosite stalactite, 8.7cm high
Stalactite section 9cm across
.
Stalactite section 3.4cm across

This mine has been producing mostly cutting grade rhodochrosite for more than 50 years. When I was in Argentina I investigated the possibility of buying some rhodochrosite and was directed to a government agency and was told I would have to deal with them. The mine was aparently owned by the gevernment and was considered part of their strategic copper reserve, though I never saw a copper mineral from the mine. Over on the western side of the Andes Mountains in Chile, the place is lousy with copper mines, but they don't have many in Argentina. Much of the rhodochrosite from the mine is a nice rose pink in color and frequently banded. Collectors cherish the stalactites of rhodochrosite from the mine which are up to about two feet tall and perhaps as much as eight inches in diameter. It they can't get a good one of those, they will even sit still for putting a cut and polished stalactite section in their collections. The stalactites are never cheap, because they can be cut up into many stalactite sections and a ready market is available for them. The best grade of rhodochrosite from the mine is called Ortiz quality, apparently named after the vein in the mine that produced it. It is a much darker pink, almost red color and is highly sought after by lapidaries for cutting into beads, cabochons and other small objects. Not much is available and it has been years since I saw any quantity of it.



RhodochrositeAustraliaNew South Wales, Yancowinna Co., Broken Hill

Rhodochrosite ~5cm wide
Rhodochrosite, 4cm across
Rhodochrosite on ? 13.4 cm across.




RhodochrositeAustraliaTasmania, Hampshire district, Kara Mines

Rhodochrosite 3cm wide
Rhodochrosite 9.5cm wide
Rhodochrosite 2.8cm wide
Rhodochrosite 5.5cm wide

Rhodochrosite from the Kara Mine at Hampshire Tasmania is an uncommon carbonate mineral, the dominant carbonate being calcite. It has been found in small amounts in various parts of the deposit mainly as small botryodal clusters with quartz veins. In 2005 it was noted close to the western contact of the underlying granite in late stage quartz, calcite veins (Sorrel Bottrill 2005). It was also noted as small cavities in the massive magnetite ore. The Rhodochrosite is considered “Calcic “(Mn75Ca25) and will often grade into manganoancalcite (Bottrill Baker2008). The Rhodochrosite appearance is light to median pink crystalline botryodal growths and prismatic crystals that have overgrown and intergrown manganoancalcite, often pseudomorphing kutnahorite; this habit is very similar to that noted at Broken Hill.
Andrew Tuma <2009>

Also see– Minerals of Kara Mine, Tasmania – Steve Sorrell, Ralph Bottrill (2005); A Catalogue of the Minerals of Tasmania; Geo. Surv. Bull. 73 – R. S. Bottrill, W. E. Baker (2008)


The mines at Broken hill are not particularly known for their rhodochrosite specimens, but they have produced some nice specimens, though most if not all are a light pink color and not very red. But good ones are still cherished by collectors. We need someone to tell us more about them and which kinds came from which mines.



RhodochrositeAustraliaTasmania, Rosebery district, Williamsford, Mt. Read, Hercules Mine.

Rhodochrosite on quartz, 3.2 mm across.



There is a local argument that many of these specimens came from the nearby Rosebery mine, where collecting was rewarded with instant dismissal, but the mineral occurs in both mines. A good number of specimens came on the market in the 1970's, and were usually in crusts of rhombohedral crystals to 10mm or so, with a pale pink colour. It is probably calcian, as at Broken Hill, and is typically associated with crystals of quartz and fibrous boulangerite. Kutnahorite also occurs at Rosebery, and is similar in appearance, but paler.



RhodochrositeBrazilSoutheast Region, Minas Gerais, Conselheiro Lafaiete (old Queluz de Minas)

Rhodochrosite on drusy rhodochrosite, 12.7 cm across.




Rhodochrosite, 15.2cm across



We need someone to tell us about the rhodochrosites from this mine.



RhodochrositeBrazilSoutheast Region, Minas Gerais, Conselheiro Lafaiete (old Queluz de Minas), Morro da Mina Mine

Rhodochrosite 11.8cm tall
Rhodochrosite 11.8cm wide

The Morro da Mina Mine is described as being an old manganese mine.


RhodochrositeBulgariaPlovdiv Oblast, Rhodope Mts. Madan

Rhodochrosite, Quartz 12cm
Rhodochrosite on Quartz 6.2cm across
Rhodochrosite, Quartz 5.8cm wide



We need someone to tell us about the rhodochrosites from this mine.



RhodochrositeBulgariaSmolyan Oblast, Rhodope Mts, Madan ore field, Batantsi Mine, Batantsi deposi

Rhodochrosite on Sphalerite 3cm wide
Rhodochrosite, 6cm wide


RhodochrositeCanadaBritish Colombia, Slocan Minind Division, Riondel, Blue Bell Mine.

Rhodochrosite, Sphalerite, Quartz 4.8cm across



We need someone to tell us about the rhodochrosite specimens from this mine.



RhodochrositeCanadaQuebec, Rouville Co. Mont Saint Hilaire, Poudrette quarry.

Rhodochrosite after Sérandite 5cm tall
Rhodochrosite on elpidite crystals, 3 cm tall.

Rhodochrosite 2.2cm tall.
Rhodochrosite 2.8cm
Rhodochrosite 2.5cm
Rhodochrosite 2.7cm

Rhodochrosite on Analcime ~4cm tall
Rhodochrosite, Aegirine, Quartz FOV 2cm

Rhodochrosite on Analcime ~8cm wide
Rhodochrosite on Analcime ~5cm wide
Rhodochrosite 3.5cm
Rhodochrosite on Aegirine FOV3mm


St. Hilaire is not particularly known for its rhodochrosite specimens, but I think it produced a greater variety of interesting rhodochrosite specimens than any other locality in the world. We need a St. Hilaire specialist to help us out on this article.



RhodochrositeChina
Guangxi Zhuang Autonomous Region, Wuzhou Prefecture, Cangwu Co., Liubao, Wutong Mine (Wudong Mine)

Rhodochrosite & Baryte 4.1cm
Rhodochrosite, & Baryte 6cm


RhodochrositeChinaGuangxi Zhuang Autonomous Region, Hezhou Prefecture, Zhongshan Co., Shanhu W-Sn deposit

Rhodochrosite & Fluorite 4.7cm




RhodochrositeChinaGuangxi Zhuang Autonomous Region, Wuzhou Prefecture

Rhodochrosite, Fluorite~ 8.5cm
Rhodochrosite & Fluorite 4.7cm
Rhodochrosite & Fluorite 2.8cm




RhodochrositeChinaGuangxi Zhuang Autonomous Region, Wuzhou Prefecture, Liubao, ("Babu") Cangwu Co., Wutong (Wudong) Mine

Rhodochrosite & Quartz 3cm
Rhodochrosite & Quartz 3.5cm wide
Rhodochrosite & Quartz 3.9cm
Rhodochrosite 8.4cm across


Rhodochrosite on Quartz, 7.8cm



With the recent flood of fine minerals from China we should not be surprised that some good rhodochrosite specimens have been found as well. We need someone to tell us about rhodochrosites from Zuang, It is possible that all the above specimens from China have all come from the same mine.


RhodochrositeFranceMidi-Pyrénées, Tarn, Réalmont, Peyrebrune, Rivet quarry

Rhodochrosite 5.6cm
Rhodochrosite & Kentrolite 3.9cm

A quarry

RhodochrositeGabonHaut-Ogooué, Moanda, Moanda Mine.

Rhodochrosite on Mn ore 13 cm tall
Rhodochrosite 7.7cm
Rhodochrosite ~10cm wide



Moanda is a shallow open cast mine that for the most part produces very uninteresting manganese ore. But every once in a while they find very pretty specimens of rhodochrosite though the crystals are never very large. All the ones I have seen have been little pointy ones. Sometimes they encounter specimens with tiny shiny black manganite crystals that will never pose a threat to their giant cousins from Germany.



RhodochrositeGermanyHesse, Limburg, Staffel, Heinricherz Mine

Rhodochrosite, FOV 5cm



We need someone to tell us about the Rhodochrosite from this locality


RhodochrositeGermanyRhineland-Palatinate, Taunus Mts, Niederneisen, Oberneisen, Rothenberg Mine (Seitersfeld)

Rhodochrosite & Quartz 6.7cm tall
Rhodochrosite 7cm wide
Rhodochrosite, 12 cm across.
Rhodochrosite ~6cm center

The two specimens pictures on the left are amongst the very best that the locality has produced. For those wishing to find out more about the Rhodochrosites from the Rhineland-Palatinate the following book contains a selection of spectacular photographs of rarities from the collections at Mainz, focussing on minerals from Rhineland-Palatinate (incl. western Siegerland, Bad Ems, the mercury deposit near Obermoschel and other mining districts) and neighbouring areas: Poser, C., and Lutz, H. (2004): Mineralien aus Rheinland-Pfalz. Landessammlung für Naturkunde (Mainz), 80 pp. (in German)

We need someone to tell us about the rhodochrosite specimens from this locality.


RhodochrositeGermanyReinland-Palatinate, Hunsrück Mts., Waldalgesheim, Dr. Geier Mine (Dr. Geir Manganese Mine, Dr. Geir Dolomite Mine) Elisenhöhe Mine)

Rhodochrosite ~7 cm across
Rhodochrosite 17cm wide
Rhodochrosite ~13cm wide
Rhodochrosite ~12cm wide

For what follows we must thank Roger Lang, obviously a charter member of the legendary "Red-Green Mafia" of Germany, who among other things points out the obvious, namely that good Rhodochrosites from German localities are highly prised and rarely on the market.

Specimens
The Dr. Geier mine has been well known for very nice rhodochrosite specimens ranging in colour from intense raspberry pink to brown. The rhodochrosite mostly forms botryoidal aggregates and reniform masses on iron/manganese oxides or ferriferous limestone/dolostone. The most sought after specimens were translucent pink single "balls" or crystal aggregates on lustrous pyrolusite/manganite providing a beautiful contrast. The "balls" mostly have a diameter of a few mm, the largest ones reached about cm size. Rhodochrosites from Waldalgesheim belong to the best of the species found in Germany. They are mentioned in the same breath as the specimens from Wolf mine, Herdorf and Oberneisen. Most of the rhodochrosite specimens from Dr. Geier mine have been recovered in the Elisenhöhe part of the mine at the so called yellow and green levels. They are comparable to the rhodochrosites from Rothenberg mine, Oberneisen, Heinricherz Mine, Staffel, and Schloßberg Mine, Geisenheim.

Other minerals worth mentioning from the Dr. Geier mine include pyrolusite and manganite crystals up to a few mm lenght as well as brownish pinkish to ivory whitish dolomite crystals up to 1.5 cm. Aragonite crystals as whitish acicular sprays reach 3 cm. Remarkeable is epsomite as up to 10 cm long acicular crystals and aggregates. Epsomite also occurs as crusts, fibrous masses and sometimes ramshorn like formations. The other minerals listed from here are only of local interest. Besides the minerals mentioned above the following species are known: calcite, chalcopyrite, copper, gypsum, "limonite", malachite, pyrite, quartz and romanèchite.

Geology
The iron and manganese ores of the Dr. Geier mine are hosted by Middle Devonian dolostones within an isoclinal through at the southern border of the variscan Rheinisches Schiefergebirge. Genetically they are related to the paleo-karst of the carbonate rocks overlain by marine sands of Oligocene age. Their formation is bound to cavities, caverns, sinkholes and dolines which formed within massive dolomite zones and zones with strong tectonic impact like fractures, joint-sets and bedding planes of the through structure during an uplift-period in the Eocene and the Lower Oligocene.

Up to 50 % of the doline fillings are Tertiary sands and clays. The ores are of mixed iron-manganese type with a Fe: Mn ratio of approx. 2:1. They contain variable amounts of muscovite (10–50%), goethite (30–50%), amorphous Mn oxides (20–30%) and manganite and pyrolusite ("Hartmanganerz", 0–22%). Their formation can be explained by a mixture of descendant colloidal solutions of Fe and Mn hydroxides under oxidizing conditions of the karst hydrography. The Mn and Fe can be deducted from weathered neighboring devonian shales of the Schiefergebirge and the dolomites. The ore grades were 12 – 20 wt.% Mn and averaging 29 wt.% Fe.

History
History
The oldest reports on manganese mining in the area date from the 17th century. At least since 1808 the Concordia mine near Seibersbach - a few km west of Waldalgesheim - was in operation. In 1832 the Sahler brothers were granted a concession to mine, followed by the Elisenhöhe claim in 1839 and the Waldalgesheim claim in 1840. Contineous mining began in 1880 by the Wandesleben brothers in open cuts. From 1885 Dr. Heinrich Claudius Geier of Mainz started extensive exploration works and sank the first shaft. These activities led to 12 concessions (mining claims) on manganese and iron. In 1904 the Gewerkschaft Braunsteinwerke Dr. Geier was founded and in 1911 all mines and concessions of the Gebr. Wandesleben GmbH (Concordia and Elisenhöhe mines, Waldalgesheim claim) were incorporated. A 7.5 km cableway to the river Rhine was built in 1912 to facilitate the ore transport to the shipping station. 1917 marks the year of the highest Mn ore production (240,853 t). At the same time the construction of the new main shaft was started (Straubenschacht). The ore was used for ironworks and partly as a pigment ore for ceramics. In 1918 673 of 1000 shares of the Gewerkschaft Braunsteinwerke Dr. Geier were acquired by Mannesmannröhren-Werke AG, Düsseldorf, followed by the purchase of another 27 shares in 1926. In 1939 all mining operations were mandated to Mannesmannröhren-Werke AG.
From 1945 to 1950 operations were controlled by the French military government, then management was mandated back to Mannesmann AG. In 1952 the Gewerkschaft Braunsteinwerke Dr. Geier was incorporated into the Gewerkschaft Mannesmann, Düsseldorf. The remaining mines Amalienhöhe, Elisenhöhe and Heerberg were modernized and extended. In the mid of the 1950s the exhaustion of the ore reserves became evident and in 1954 mining of the huge dolomite reserves started. Since 1964 a part of the dolomite was processed to dolomite sinter in rotary furnaces. The products were transported railway-bound via the Rheinstollen gallery to the shipping facility north of Bingen. During these years the mine increasingly suffered from high production costs compared to open pit dolomite mines and finally was not able to compete on the market so in 1971 the mine was closed. In total about 6.4 million tonnes Fe-Mn ore and about 2.5 million tonnes of dolomite had been recovered.

The surface installations of the Straubenschacht site are worth to be specially mentioned. The ensemble is considered to be a most important monument of mining related architecture in Germany. The impressive neo-baroque style site was planned by Markwort & Seibert from Darmstadt. Unfortunately the buildings partly are in a very bad shape today and one can only hope that there will be strong efforts to conserve and restore this outstanding cultural heritage in the near future.

References
References:
M. Berghäuser (2009): Rhodochrosit und seine Begleitmineralien aus der Grube "Dr.Geier" im Hunsrück. - Lapis, Vol. 34, Nr.3, 13-19.
H. Bottke (1969): Die Eisenmanganerze der Grube Dr. Geier bei Bingen/Rhein als Verwitterungsbildungen des Mangans vom Typ Lindener Mark. - Mineralium Deposita, Vol. 4, Nr 4, 355-367.
O. Ermann (1951): Die Eisen- und Manganerzlagerstätten des östlichen Hunsrücks (im Gebiete von Stromberg-Bingerbrück). - Der Aufschluss, Vol.2, Nr.6, 85-87.
K.Klemp (1987): Grube Dr. Geier - Monument des deutschen Erzbergbaus. - Biebertal, 1987.
W. Rosenberger (1971): Beschreibung rheinland-pfälzischer Bergamtsbezirke. - Vol. 3, Bad Marienberg 1971.
A. Vierschilling (1910): Die Eisen- und Manganerzlagerstätten im Hunsrück und Soonwald. - Z. Prakt. Geol. 18, 393-431.



RhodochrositeGermanyReinland-Palatinate, Siegerland, Herdorf, Wolf Mine.

Rhodochrosite ~6cm wide
Rhodochrosite 6.6cm wide
Rhodochrosite 3.2cm tall
Rhodochrosite 3.9cm tall
Rhodochrosite 4.6cm wide
Rhodochrosite 4.5cm
Specimens
Rhodochrosite from the Wolf mine is probably one of the best known mineral species from Germany in the world. The specimens from there are considered to be the best of Europe and they are present in museums and collections worldwide. Finds were restricted to the active mining period so nowadays specimens from there are highly sought and the prices high. The rhodochrosite varies in colour from salmon pinkish to raspberry pink or orange-reddish to brownish. Typically it is associated with limonitic matrix where it forms crystals and aggregates in vugs of the ore. The habit varies from single millet-seed shaped crystals to star or hedgehog shaped aggregates of those, barrel and cone shaped crystals as well as sheave-like aggregates. Most of the crystals are built by numerous small steep scalenohedral subindividues. The crystals reach up to about 2 cm size, larger crystals have been extremely rare. The majority of the crystallized samples show crystal sizes from a few mm to about 1 cm. Also botroydal and spherical aggregates and coatings were common. The aggregates often show a 'raspberry' like habit ('Himbeerspat' - raspberry spar - Breithaupt, 1832). The most beautiful specimens are of a deep orange-pink colour, they are translucent and provide a great contrast to the limonite matrix. Combo specimens of rhodochrosite with malachite-coated crystals of native copper (reaching sizes of up to about 3 cm) on matrix are the most interesting association of the Wolf mine. The best and richest specimens were found in a zone around the 350 m level.

Geology
The Wolf mine belongs to the Siegerland siderite district where mining goes back to celtic times. The ore of this district is primarily of sideritic type with more or less developed oxidation zones where limonite/goethite is prevalent. Also Pb, Zn, Cu and Ag as well as Co and Ni minerals occurred frequently - especially at the upper levels - and mostly have been mined at the beginning of modern mining. Mineralization is of hydrothermal origin and developed as veins in Devonian sedimentary rocks (shales, sand- and siltstone) of the Rheinisches Schiefergebirge. The Wolf mine was characterized by a deeply developed oxidation zone (to a depth of almost 400 m), probably due to the influence of the intrusion of tertiary basaltic melts in the neighborhood which provided thermal energy and fluid flow favouring the alteration of the siderite veins. The rhodochrosite finds were restricted to the limonitic ores of the oxidation zone. Towards depth the ore became sideritic with quartz gangue and towards the roots of the veins the quartz content increased.

History
The Wolf mine is one of the younger mines of the district. Mining started about 1870 when limonite ore was extracted via adits. In 1890 the Reifenrath brothers from Neunkirchen acquired the mine and sank a shaft. Having reached a depth of 300 m the mine was sold in 1917 to Krupp, Essen and modernized by the installation of new steam machines for haulage. The water pumps were fitted with electric power supply. Consequently the extraction tonnage increased to 4,000 - 5,000 tonnes per month. During the 1920s 200 to 250 miners worked at the mine. In 1925 the mining stopped due to economic reasons. The surface installations were demolished and the mine was flooded. 10 years later the reopening was prepared by pumping out the mine and the building of new surface installations including an electric hauling machine and a cableway to transport the ore to the central processing plant at the Füsseberg mine in Daaden-Biersorf. On 1st of may 1937 the mine was then reopened again. With an extraction of 84,000 tonnes of ore the year 1944 marks the best yield in the history of the mine. But in 1945 the mine closed again due to World War II impact and the mine was flooded again. In 1953/54 the last mining period at the Wolf mine started: it then was consolidated with the San Fernando, Friedrich-Wilhelm, Füsseberg and Große Burg mines to a combined mining complex. The mined ore was transported underground to the San Fernando mine and hauled and processed there. Finally in 1962 the mine was completely closed.

References
R. Bode (1980): Die Grube Wolf in Herdorf, Siegerland. - Emser Hefte 3, 6-35.
A. Hoffmann (1964): Beschreibung rheinland-pfälzischer Bergamtsbezirke - Band 1 Bergamtsbezirk Betzdorf. - Verlag Glückauf, Essen.
H.-G. Koch (1982): Erzväter - Berg- und Hüttenleute im Siegerland und Westerwald. - Verlag Gudrun Koch, Siegen.
W. Richartz (1979): Rhodochrosit von der Grube Wolf. - LAPIS, Vol. 4, Nr. 10, 12-16.



RhodochrositeGermanyRhineland-Palatinate, Westerwald, Wied Iron Spar District, Altenkirchen, Bürdenbach, Louise Mine.

Rhodochrosite on Mn ore, 8.5 cm tall



We need a German specialist to tell us about rhodochrosite from this mine.



RhodochrositeGreeceMacedonia Department, Chalkidiki Prefecture, Cassandra Mine.

Rhodochrosite, Calcite, Gypsum 7cm
Rhodochrosite 9.2cm tall
Rhodochrosite 4.5cm across
Rhodochrosite on ? 7 cm across
Rhodochrosite 9.5cm



We need someone who know about Greek minerals to tell us about the specimens from this mine.



RhodochrositeItalyLiguria, Genova Province, Ne, Graveglia Valley, Reppia, Valgraveglia Mine (Gambatesa Mine)

Rhodochrosite ~4cm wide




RhodochrositeJapanHokkaido Island, Shiribeshi Province, Shakotan peninsula, Inakuraishi Mine.

Rhodochrosite ~12cm wide



Rhodochrosite, Quartz 8.4 cm
Rhodochrosite cut & polished ~6cm wide
Rhodochrosite 10cm



It is obvious from what Alfredo Petrov tell us below that we have not even scratched the surface of what is available from this and other Hokkaido mines and that the pictures above are of what are almost certainly rather poor specimens.

Several big mines in southwestern Hokkaido worked hydrothermal rhodochrosite veins traversing Tertiary (mainly Miocene) sediments and volcanic agglomerates. As pink rhombohedra to several cm (but commonly only up to 1cm) in cavities and as gangue in sphalerite-chalcopyrite-pyrite ore at the Oue (or O'e) mine; the Senzai rhodochrosite vein here, one of the longest in Japan with a strike of 1.5km in Tertiary sediments, was mined as Mn ore. Sometimes as beautiful banded masses of different tones of pink, alternating with sphalerite and pyrite bands. Light pink, lenticular rhombohedra to almost 2cm form crusts lining cavities in en echelon rhodochrosite veins crossing Miocene propylite at the Inakuraishi mine; also as compact massive crusts to 5cm thick formed of bands from 0.3 to 10mm wide, varying from pinkish white to deep pink, associated with pyrite and sphalerite; also as pink stalactites to 15cm long and 2cm diameter, looking very similar to the famous Argentine ones but a lighter pink color. Inakuraishi was the largest Mn deposit in Japan (1944 production 72,000 tons ore @ 27% Mn); the largest vein measured 900m, x 5m thick, with known dip of over 250m. After metal mining ceased, there was some minor commercial production of rhodochrosite for ornamental use. In the Yakumo silver mine as rhombic crystals up to several cm in rhodochrosite-alabandite-sphalerite-galena ore, with pyrite, marcasite, pyrrhotine, pyrargyrite and tetrahedrite-tennantite; rhodochrosite veins in Tertiary rock were also mined here as Mn ore. As at the Inakuraishi mine, there was mining here for ornamental rhodochrosite after metal production had ended, and there were beautifully banded structures of fine light pink rhodochrosite alternating with sphalerite-pyrite-galena bands. Another big producer of vein rhodochrosite in southwestern Hokkaido was the Johkoku mine (type locality for jokokuite) which yielded 105,652 tons of crude rhodochrosite in one year (1958)! The Imai-Ishizaki mine and the Toyoha mine (type locality for toyohaite) were big rhodochrosite ore producers too.
Most Hokkaido rhodochrosite specimens in dealer stock are labelled as being from the Inakuraishi mine and to be "old" specimens. I suspect that quite a few "Inakuraishi" specimens might be from other Hokkaido mines, as the parageneses are very similar. The best quality specimens came out after mining for manganese ore had ceased and the mines were later being worked on a small scale just for specimens and for lapidary rough, ie well after the end of WWII, and mostly the 1980s. The truly "old" specimens were not nearly as good. Also, since most classic japanese minerals are indeed "old", and very hard to get nowadays, they tend to be priced high by dealers, and rightfully so; but rhodochrosites, however, were mined in relatively large quantity and are still readily available in Japan, so the prices asked for such specimens outside Japan are probably rather too high.



RhodochrositeJapanHonshu Island, Tohoku Region, Aomori Prefecture, Naka-Tsugaru-gun, Nishimeya-mura, Oppu Mine.

Rhodochrosite on Quartz 8.7cm across



Rhodochrosite 9.1cm
Rhodochrosite on Mn ore, 5.1 cm across
Rhodochrosite 7.3cm across
Rhodochrosite 11cm tall

Rhodochrosite 16cm wide



We need to have an person knowledgeable about Japanese minerals tell us about the rhodochrosites from this old and famous mine. This mine is better known for its massive/botryoidal forms of rhodochrosite than its crystals.



RhodochrositeJapanHonshu Island, Kanto Region, Tochigi, Kanuma

Rhodochrosite ~4.5cm across



We need someone to tell us about the rhodochrosite from this locality.


RhodochrositeKazakhstanZhezqazghan Oblysy (Dzezkazgan Oblast'; Dzhezkazgan Oblast'; Djezkazgan Oblast'; Jezkazgan Oblast'), Balqash (Balkhash; Karatas; Prebalkhashie) Region, Kounrad Massif

Rhodochrosite, Bertrandite & Fluorite 13.5 cm across.



We need someone to tell us about the rhodochrosite from this locality. Is this the same locality as the Kazakhstan rhodochrosite we show below?


RhodochrositeKazakhstanAtasu-Karazhal-Zhayrem area, Ushkatan (Ushkatyn) deposit.

Rhodochrosite 5.3cm across
Rhodochrosite, 7 cm tall.

We need someone to tell us something about the rhodochrosites from the Ushkatan deposit.



RhodochrositeKosovoSysert' district, Tumet river, Kosovo, Kosovska Mitrovica, Terpča valley, Terpča complex.

Rhodochrosite & Pyrite 7.6 cm across



We need someone to tell us about the rhodochrosite from Trepča.



RhodochrositeMexicoChihuahua, Santa Eulalia District, Potosi Mine

Rhodochrosite 6.5cm across
Rhodochrosite 6.4cm across
Rhodochrosite & Sphalerite 3cm
Rhodochrosite & Fluorite 5.8cm
Rhodochrosite 6.2cm wide
Rhodochrosite 4.4cm across
Rhodochrosite 4.4cm wide
Rhodochrosite 5.5cm across
Rhodochrosite 2.4cm tall
Rhodochrosite ~9cm wide
Rhodochrosite ~9cm wide


Rhodochrosite & Quartz 7.8cm tall



Rhodocrosite specimens were found between the 10th and 11th levels of the Potosi mine in abundant vugs. The habits are medium-pink botyroidal masses, bright pink rhombohedra and rarer blood red crystals. Brownish elongated scalenohedral crystals to 8cm "cathedral rhodochrosite" were found circa 1987. They are not very common. Of all the times I have bought specimens at the mine (five or six times) I was never offered a good specimen of rhodochrosite.



RhodochrositeMexicoChihuahua, Mun. de Chihuahua, Ejido Esperanza, Otra Estrella claim

Rhodochrosite 5.2mm tall




RhodochrositeMexicoGuerro, Mun. de Taxco, Taxco de Alarcón (Taxco), Remedios Mine.

Rhodochrosite on Ilvaite 9.3cm wide
Rhodochrosite on Quartz 5.5cm wide
Rhodochrosite 3.2cm tall
Rhodochrosite 5cm tall
Rhodochrosite & Quartz 6.5cm
Rhodochrosite on Quartz 6.4cm wide



RhodochrositeMexicoSonora, Mun. de Cananea, Cananea

Rhodochrosite & Pyrite ~7cm wide
Rhodochrosite ~5cm wide

We need someone to tell us about the Rhodochrosites from Cananea


RhodochrositeNew CaledoniaSouthern Province, Yaté Commune, Goro

Rhodochrosite FOV~5mm




RhodochrositePeruAncash Department, Bolognesi Province, Pachapaqui District.

Rhodochrosite 3.9 cm across
Rhodochrosite on Quartz 9.5cm


Rhodochrosite on Quartz 6.5cm tall
Rhodochrosite on Quartz 12.7 cm
.
Rhodochrosite on Quartz 3.5cm wide

The base metal underground mines of the Pachiqaqui district has produced a wide selection of pink to pale pink rhodochrosite specimens. Some of them are so pale that I wonder if they are even rhodochrosite. Some of them are quite striking. Over the years probably some thousands of specimens have been produced and sometimes in Lima you could buy them by the Kg.



RhodochrositePeruAncash Department, Pallasca Province, Pasto Bueno District, Pasto Bueno Mine.

Rhodochrosite on Fluorite ~4.5cm tall
Rhodochrosite, Huebnerite ~4.5cm wide
Rhodochrosite, Quartz 8cm>
Rhodochrosite on Quartz 2.1cm tall
Rhodochrosite ~8cm wide
Rhodochrosite ~8cm across
Rhodochrosite on Quartz ~7cm tall
Rhodochrosite 4.8cm tall
Rhodochrosite ~20 cm



Pasto Bueno is a little company town where they mine tungsten and the mine was productive prior to World War II and mining is still going on. Until about 1960 almost all of the specimens produced were run through the mill. The little mine known as Huayllapon, is located some distance above the town and the main tungsten mine. This the mine that has produced most of the Rhodochrosites and Hübnerite specimens that the locality is famous for. The good Rhodochrosites from this mine were never abundant and I would estimate that there less than 100 good specimens were produced. They were usually associated with quartz and very rarely hübnerite though I don't think I ever saw a really good Rhodochrosite/Hübnerite combination. When the mine started to produce good rhodochrosite specimens, they rivaled the best in the world, but later the Sweet Home mine was reopened by Brian Lees and the ones he produced put the Peruvian rhodochrosites in the shade. The first really good rhodochrosite that came out of the camp was sold to an American dealer for about $15 by the company geologist mostly because he thought it was not rhodochrosite because it did not bubble when he put acid on it. Needless to say it was sold at a substantial mark up. In a country of remote mines, this was very remote and not a healthy place to work or visit. A friend of mine got hepatitis while visiting the camp and the camp doctor told me that there was a 75% incidence of tuberculosis and a 120% incidence of hepatitis in the camp. The mine is so high up ~15000 feet that the mine managers house was the lowest one in the camp.



RhodochrositePeruJunín Departmen, Yauli Province, Morococha District, Manuelita Mine.

Rhodochrosite on Pyrite 3.3cm across
Rhodochrosite on Sphalerite 7.4cm
Rhodochrosite on Pyrite 5.4cm across
Rhodochrosite on Quartz 8.9cm
Rhodochrosite 10cm wide
Rhodochrosite & Quartz 8.2cm tall
Rhodochrosite 7.1cm wide
Rhodochrosite on Quartz 8cm cross
Rhodochrosite 9cm tall
Rhodochrosite 5.4cm
Rhodochrosite on Pyrite 6.4cm wide
Rhodochrosite & Quartz 7.8cm tall

This mine has never produced many good rhodochrosites, but over a period of perhaps 20 years there has been a steady trickle of them coming out. All total I may have made about 15 trips to Peru to buy minerals for my business and don't ever recall being offered a quantity of rhodochrosite specimens from this mine. I was once able to buy a very nice small specimen once on the street from a runner, and that was about it.



RhodochrositePeruJunín Department, Yauli Province, Morococha District, Santa Rita Mine

Rhodochrosite 5cm




RhodochrositePeruLima Department, Oyon Province, Uchucchacua Mine

Rhodochrosite 9cm tall
Rhodochrosite 4.6cm tall
Rhodochrosite & Fluorite 8.2cm wide
Rhodochrosite 4.5cm tall
Rhodochrosite 3.6cm wide
Rhodochrosite 50cm wide

The Uchucchacua Mine is a silver and base metal at an altitude of about 14 thousand feet like most of the miners n Peru. These matrix on these specimens is particularly difficult to trim and they always seem to break perpendicular to the surface of the specimen where the crystals are located and the matrix is very tough. You have to use a diamond saw to trim them properly. Because of the difficulty of trimming, many specimens from this locality have the rhodochrosite crystals glued back on the matrix. The mine has produced thousands of specimens and probably several hundred good ones, but the good ones were always hard to get.



RhodochrositePeruPasco Department, San Jose de Huayllay District, Huaron Mining District, Huaron Mines.

Rhodochrosite on Quartz 8cm wide
Rhodochrosite & Quartz FOV 4cm
Rhodochrosite on Pyrite 4.3cm wide



Rhodochrosite specimens from the Huaron mines are quite rare. I have purchased hundreds of pounds of specimens from this mine over the years and there was not a single decent rhodochrosite among them and in fact I don't ever remember a single rhodochrosite in all those specimens. Huaron is much better known for its little prismatic quartz crystals associated with pyrite crystals.



RhodochrositeRomaniaHunedoara Co. Sacarîmb (Sãcãrâmb; Szekerembe; Nagyág)

Rhodochrosite ~9cm wide




RhodochrositeRoumaniaMaramures Co. Baia Sprie (Felsöbánya).

Calcite on Rhodochrosite 8cm across



We need someone to tell us something about rhodochrosite from Felsöbánya.



RhodochrositeRomaniaMaramures Co., Cavnic

Rhodochrosite on Quartz 9 cm wide.
Rhodochrosite on Quartz 9.6cm wide
Rhodochrosite & Quartz 10cm wide
Rhodochrosite on Quartz 7cm wide

Rhodochrosite on Quartz 5.5cm wide
Rhodochrosite, Quartz 6.4cm wide
Rhodochrosite 5cm wide
Rhodochrosite & Quartz 8cm wide

We need someone to tell us something about the rhodochrosites from Cavnic. It would appear that most of the good specimens come from the Boldut Mine.



RhodochrositeSlovakiaBystrica Region

Rhodochrosite, 9 cm across.



We need someone to tell us about the rhodochrosites from this locality.



RhodochrositeSouth Africa, Republic of.Northern Cape Province, Kalahari Manganese fields.

Rhodochrosite 12cm wide
Rhodochrosite on Mn ore 12cm wide
Rhodochrosite & Barite 5.4cm
Rhodochrosite on Manganite 4.6cm wide
Rhodochrosite 5cm tall
Rhodochrosite 5.2cm wide

There are a number of manganese mines in the Lalahari Manganese fields and the specimens pictured above are probably mostly from Wessels and N'Chwaning mines. Below are more pictures of specimens from these mines. We need an expert on these deposits to step up and clarify which kinds of rhodochrosite specimens come from each of the mines.



RhodochrositeSouth Africa, Republic ofNorthern Cape Province, Kalahari manganese fields, Hotazel mine

Rhodochrosite ~7cm wide
Rhodochrosite on Manganite ~6.5cm wide
Rhodochrosite, Manganite 28mm
Rhodochrosite 4cm wide
Rhodochrosite ~6cm wide
Rhodochrosite 3.6cm tall

We need someone to tell us about the rhodochrosite from the Hotazel mine.


RhocochrositeSouth Africa, Republic of.Northern Cape Province, Kalahari manganese fields, Hotazel, Wessels Mine (Wessel's Mine).

Rhodo 5.4cm
Rhodochrosite 6.5cm wide
Rhodochrosite 5cm tall
Rhodochrosite 6.4cm wide

We need someone to tell us more about the rhodochrosites from the Wessels Mine.



RhodochrositeSouth Africa, Republic of.Northern Cape Province, Kalahari manganese fields, N'Chwaning Mines.

Rhodochrosite 8cm wide
Rhodochrosite on Mn ore 6cm wide
Rhodochrosite 3.8cm wide
Rhodochrosite 4.8cm tall
Rhodochrosite 11.3cm
Rhodochrosite 8.2cm wide
Rhodochrosite 2.5cm wide
Rhodochrosite 3.3cm wide

Rhodochrosite 3cm tall
Rhodochrosite on Manganite 6cm side
Rhodochrosite 2.5cm wide
Rhodochrosite 3cm wide

Probably most of the best specimens of rhodochrosite from Hotazel came from this mine. Prosper Williams a mineral dealer was the first to bring out specimens from this area and I remember wanting one badly but they were just too expensive for me to buy. Later better ones were found at the N'chwaning and I got a crack at some of those, but I never got a great one. Probably more than 1000 specimens have been produced, but probably less ten great ones. One of the great ones is know as the "snail" and belongs to Bill Larson of Fallbrook, California. Some day I may tell the story of how he got it.



RhodochrositeUkraineCrimea Oblast', Kerch peninsula.

Rhodochrosite after sea shells, 3.8cm
Rhodochrosite after sea shells 8cm

I thought these were rather remarkable. The Kertch peninsula is perhaps better know for its specimens of the phosphate minerals metavivianite and anapaite which are sometimes also found growing inside fossil sea shells




RhodochrositeUnited KingdomEngland, Cornwall, St. Just District, Botallack - Pendeen Area, St. Just District, Botallack Mine

Rhodochrosite ~5cm wide
Rhodochrosite 7cm wide

This is a classic old Cornish tin mine dramatically poised on the scenic cliffs above the sea. The mine drove galleries out under the sea and there are stories that the miners could hear the waved breaking on the rocks above them and the water seeping into the mine would taste of salt. It never produced specimens you would kill your grandmother for and probably is famous because it famous. Better know or its cassiterite and axinite specimens one generally does not think of it producing rhodochrosite specimens, but it did sparingly.


RhodochrositeUKEngland, Sommerset, Long Ashton, Durnford Quarry

Rhodo. with tiny black Manganite
Rhodochrosite ~20 cm wide
Rhodochrosite 7cm wide



"About the find .... one of my best collecting days in the UK !! Found memories ....
It was on March 24th 2007 during a Russell Society field trip, and I believe about 4/5 of us were lucky enough on the day. One week after there was not much left I heard and rest went probably to the crusher. I would not count the find in flats, but would say about 15 - 20 of good/top quality were collected on the day (kept 4 and gave a few - sic !!). Some had also Wulfenite but not on the specimen I collected, but I believe the one uploaded was the largest Rhodo. cavity found."1. The Durnford Quarry is a limestone quarry and there were a few small wulfenite crystals found. Emmanuel reports at least one orange crystal of about 8mm was found.
1. Emmanuel Bravais, email communication 2009.

The material from Durnford Quarry is largely rhodochrosite. I ran X-ray powder diffraction (XRD) and Energy dispersive X-ray analysis (EDX/EDS) on material from the original find (2007) and several XRD runs produced perfect matches with the patterns for rhodochrosite. Questions were raised over what the true manganese content was, so I ran the XRD powder by EDS on a an SEM stub in 2008 and it came back with the ratio 10.47-11.54% Mn: 1.38-1.70 % Ca: 0.46-0.55 % Mg: no detectable Fe. Obviously this is semi-quantitative as you cannot measure the carbonate component, but clearly it is manganese-dominant. The locality was kept vague, due to issues regarding people collecting there without permission, but most of the new specimens sold during 2007/2008 as Merehead Quarry, are actually from Durnford Quarry. Merehead Quarry as noted earlier did produce pink samples, but most have turned out to be manganese-rich calcite.



RhodochrositeUSAClear Creek Co., Dailey District (Jones Pass District)

Rhodochrosite on Quartz ~9cm tall



RhodochrositeUSAColorado, Eagle Co., Gillman District, Gillman, Eagle Mine.

Rhodochrosite, Pyrite Sphalerite 5cm
Rhodochrosite 3.1cm

A cavity in pyrite-sphalerite ores was discovered on the 20 level of the Rocky Point orebody in 1976. The crystals are pale to deep rose-pink in color (less than 1% iron) disc shaped and range in size from 0.5 to 2.5cm.


RhodochrositeUSAColorado, Gilpin Co. Central City District, Moose Mine.

Rhodochrosite 7.5cm across



Numerous crystals and cleavage fragments of dark red rhodochrosite were found during mining and on the dumps. Red rhombohedral crystals to 7.5cm were found in operations in the 1980's on the 150 foot level.


RhodochrositeUSAColorado, Hinsdale Co., Park District (Sherman District), Cinnamon Pass, Champion Mine

Rhodochrosite 8.9cm wide




RhodochrositeUSAColorado, Lake Co., Climax District, Climax Mine.

Rhodochrosite on quartz 11.3 cm
Rhodochrosite & Quartz ~2.4cm

Climax is a big molybdenum mine at about 11,000 feet altitude and though not know for many good specimens, once in a while the miners encountered rhodochrosite specimens, but they were not common. The rhombohedral crystals are a rich red color and occur as single crystals or intergrown groups to 5cm. Most of the crystals were obtained from underground areas, although the majority of the mining was done in the open pit.


RhodochrositeUSAColorado, Lake County, Leadville District, Alicante, John Reed Mine.

Rhodochrosite 2.3cm tall>



Red to deep rose rhombohedrons to 2.5cm although the better specimens are of the order of 1cm. Some of the rhodochrosite from this mine has been facetted (a 8.4 carat stone in the Denver museum collection).


RhodochrositeUSAColorado, Ouray Co., Daniel Bonanza Mine.

Rhodochrosite, quartz, 3.8 cm across



We need someone to tell us something more about the rhodochrosite specimens from the Daniel Bonanza Mine.




RhodochrositeUSAColorado, Ouray Co., Ouray District, Ouray, Bear Creek Canyon, Grizzly Bear Mine

Rhodochrosite, Quartz, 9.5 cm high



Locality photos one two.
Grizzly Bear Mine produced translucent rose-red rhombohedra. Pink crystals on green quartz (chlorite included) were actually found in the Zanett tunnel (driven toward the Grizzly Bear vein).



RhodochrositeUSAColorado, Park Co., Alma District, Mount Bross, Sweet Home Mine.

Rhodochrosite on Sphalerite ~20cm wide?




Rhodochrosite, Quartz, Fluorite 11cm wide




Rhodochrosite on Quartz 6.5cm wide




Rhodochrosite, Quartz & Pyrite 5.2cm




Rhodochrosite on Quartz with Fluorite 8.4cm wide




Rhodochrosite on Quartz ~11cm wide




Rhodochrosite on Quartz ~20 cm wide
Rhodochrosite on Quartz 6cm tall

Rhodochrosite, Fluorite 6cm wide
Rhodochrosite, Tetrahedrite 5.2cm tall
Rhodochrosite ~8cm
Rhodochrosite & Quartz 2.7cm tall

The Sweet Home Mine has produced more fine rhodochrosites than another mine in the world. It also has the distinction of being one of the few mines that has ever been able to support a mining operation from the sale of specimens alone. Several hundred fine rhodochrosites specimens have been produced and some of them have sold for more than a million dollars I think one of them may have been sold for several million dollars. The story about these specimens and the mining of them is interesting to read. Brian Lees of the Collectors edge was the driving force behind the project and he was meticulous in the care with which the specimens were extracted and developed new tools and methods to do it successfully. It was a small mining operation but a very careful one. A normal mining operations would have destroyed most of the specimens.1
1. Mineralogical Record, Sweet Home Mine Issue, July-August, 1998, Vol. 29 No. 4.



RhodochrositeUSAColorado, San Juan Co. Silverton District, Howardsville, American Tunnel Mine.

Rhodochrosite & Fluorite ~10cm wide
Rhodochrosite on Fluorite ~5cm wide
Rhodochrosite 3.5cm across
Rhodochrosite 5cm across
Rhodochrosite & Chalcopyrite ~9cm wide
Rhodochrosite on Quartz ~7cm wide

Rhodochrosite & Gypsum ~7cm wide
Rhodochrosite & Fluorite ~9cm wide
Rhodo, Fluorite, Quartz ~10cm
Rhodochrosite ~13cm wide


Rhodochrosite on Quartz ~6cm tall
Rhodochrosite & Gypsum ~7cm wide
.
Rhodochrosite ~9cm wide

At one time the rhodochrosite specimens from this mine were abundant. Thousand of them were produced. The best of them were associated with white quartz and somewhat rounded subdued green fluorite crystals. We could use some help here describing the rhodochrosite specimens from this mine.



RhodochrositeUSAMontana, Silver Bow Co., Butte District, Butte.

Rhodochrosite & Quartz 5cm wide
Rhodochrosite & Quartz 6.4cm wide

Rhodochrosite & Quartz 4cm wide
Rhodochrosite 3.6cm tall
Rhodochrosite 5.1cm
Rhodochrosite 5.1cm wide
Rhodochrosite 4.7cm wide



Butte Montana has produced a surprising variety of rhodochrosite specimens though few of them are really red. We could use someone to help in describing the rhodochrosite specimens from this locality.



RhodochrositeUSANevada, Humboldt Co., Buffalo Mountain District, Lone Tree Mine, Sequoia Pit

Rhodochrosite & Bartie 5cm
Rhodochrosite n& Bartie 3cm


RhodochrositeUSANew Jersey, Sussex Co., Franklin Mining District, New Jersey

Rhodochrosite ~9cm wide



We need someone to tell us about Rhodochrosite specimens from Franklin


RhodochrositeUSANorth Carolina, Cleveland Co., Kings Mountain District, Foote Lithium Co. Mine

Rhodochrosite & Apatite 7.5cm
Rhodochrosite & Bikitaite ~7.5cm

We need someone to tell us about Rhodochrosite specimens from the Foote Mine


RhodochrositUSA
Utah, Utah Co., East Tintic Mts, East Tintic District, Burgin Mine,

Rhodochrosite, 5.5cm wide




RhodochrositeUSAWisconson, Iron Co., Montreal, Montreal Mine (Ottawa; 33 Company Mine; Trimble; Odanah; Moore; Jupiter; Bourne; Sec. 33 Mine)

Rhodochrosite on ? 8.6 cm tall.



Found in the lower levels of the Montreal Mine (38th level of #5 shaft). Crystals are light pink in color and occur as rhombohedroms or better as radiating groups of thin prismatic crystals to 3cm in length on manganite.

Do you know of other rhodochrosite localities that should be included here? We would like to hear about them.



Click here to view Best Minerals R and here for Best Minerals A to Z and here for Fast Navigation of completed Best Minerals articles.

Rock Currier
Crystals not pistols.



Edited 169 time(s). Last edit at 04/27/2012 11:50AM by Rock Currier.
avatar Re: Rhodochrosite
January 03, 2009 01:50PM
    
Deeper red color is due to higher purity of the rhodochrosite.
Also need to add N'Chwaning II Mine, N'Chwaning Mines, Kalahari manganese fields, Northern Cape Province, South Africa (also have never been cheap), Oppu mine Japan, Santa Eulalia
avatar Re: Rhodochrosite
January 03, 2009 03:53PM
Dear Dave, Thanks for your comments.
Yes, I know I need to add the Kuraman rhodochrosites and those from about 25 additional localities, but I only got as far as Greece in the alphabet at the time of your post. I thought I would say something about the probable high manganese content of red rhodochrosite. Dana lists some analysis for Rhodochrosite, the John Reed mine material among them (almost pure manganese carbonate) and I thought I would ask Brian Lees if he had ever had done an analysis on his rhodos from the Sweet home. Do you know of any studies that link manganese content to how red the specimens are?

Rock Currier
Crystals not pistols.
avatar Re: Rhodochrosite
January 03, 2009 03:58PM
    
Yes, there is an article about it in the Min Rec Sweet Home issue.
avatar Re: Rhodochrosite
January 04, 2009 02:13PM
Dave,
Thanks for the reference. I had forgotten all about it. I have made reference to it in the article/gallery or what ever you want to call it. I have finally finished making the initial entries, but when the forum is opened to the public I hope there will be a lot of people who would like to contribute more data and information to help flesh out the individual entries and even suggest localities that are not included here.

Rock Currier
Crystals not pistols.
avatar Re: Rhodochrosite
January 04, 2009 03:52PM
    
I am wondering if you are diluting the best a bit with the rhodos. Personally, I think of the best as either the best color, size or crystal form. For rhodos my votes would be for Kalahari, Sweet Home, Argentina, Peru and maybe Santa Eulalia. While other localities produce some pretty specimens, these localities are so much better in crystal color, clarity, size and form to make the others also rans (also they do tend to be much dearer).
avatar Re: Rhodochrosite
January 04, 2009 04:30PM
Dave,
I am not sure what you mean. Do you mean I should not include as many rhodochrosite localities as I have?

Rock Currier
Crystals not pistols.
avatar Re: Rhodochrosite
January 04, 2009 04:53PM
    
Personally I would lean that way. The ones I listed, I think you could easily defend as the best specimens of rhodochrosite. While some of the other localities produce cute specimens, I really don't think they are "best" or in the same class with Sweet Home and Kalahari specimens (or anywhere near the cost of a top line specimen). As a test, if you had a cabinet full of rhodo specimens from these localities, where would be the drool on the glass?
avatar Re: Rhodochrosite
January 04, 2009 05:59PM
    
If I remember the gold stars we put on locality listed minerals were for the best specimens world wide and the silver stars were for very high quality.
I see a little confusion here over the silver stars. Perhaps silver could mean the best stuff from that locality. While you might make a case for the Kertch Rhodo pseudos to be one one of the world's best fossils, certainly one of the most attractive and I would rate like Australian fossil opals, it doesn't appraoch the best Sweet Home or Kalahari Rhodos.

There will be argument over whether Sweet home or Kalahari is world's best, but almost all would agree that both should be included. Putting the best stuff from a locality in here opens up the possibility of massive sulfides being the best, say from Noranda mines. Tsumeb germanites and renierites come to mind as well. Fortunately there is that Killer crystallised Germanite, but I think the Tsumeb Renierites were micro xls at best with other localities producing better xls. So opening up to the best from a locality could open this to Quarry road rock, I think the info about a large amount of really good silver star minerals is worth having. It is not clear to me how to draw the line. Perhaps when this is opened up as a message board people could vote as to whether an item should go in the moderated best stuff archive and what doesn't make the vote could be stuck in the locality pages. There is lots of good info in these "silver accounts".

Any rhodo collector would give their eye teeth to have a rhodo collection with these photoed rhodos, even if they are not all the world's best.



Edited 1 time(s). Last edit at 01/04/2009 06:02PM by Rob Woodside.
avatar Re: Rhodochrosite
January 05, 2009 04:45AM
I think I should say at this point, that the name that was given to to the Best Minerals forum was not mine, but Dave's. I think I wanted something like The Best Stuff. Perhaps it would be better to name it "The Best Stuff from Everywhere". It was never my intention to limit the descriptions only to the best stuff from the best localities. If you look at some of the more obscure and rare minerals I have described you will see that the intent is to describe the best specimens from as many localities as may be considered important and or interesting.

Since in reality it will be impossible to describe the best grains of sand on a particular beach, the task becomes to judge what is important and and interesting. This is always going to be a judgment call. Is there any way to know how many localities are represented by pictures verses the number of localities other than going in and just counting them by hand?To some extent the pictures uploaded to Mindat have already made a first cut selection of what is important and interesting. I would suspect that of every ten localities listed on mindat that only one of them has had a picture of a mineral from that locality submitted. They were all interesting enough and important enough to someone that they bothered to take a picture of them and go to the trouble to up load them. Needless to say I would not want to use them all in the articles I have created this far and will in the future. In fact, some of the pictures are borderline as far as I am concerned and I will not hesitate to upgrade them when better pictures and pictures of better specimens become available.

I tend to avoid pictures of micro specimens for common minerals like azurite etc, but if micro crystals are as good as can be found for a species, then by all means I feel they should be included. Some species have one locality for macro type specimens and the rest are mostly micro. I would tend to throw in a few photos of the micro stuff from the other localities along with pictures from the macro locality. The idea of these articles is to give the collector a resource to be able to put his and other peoples specimens in proportion to the best that is our there in the real world. Showing images of only the best specimens from the best localities will not do that. Further, in each article like the example of Aluminum, I want to give the reader some information on how abundant the specimens are. I want to come as close as I can to answering all the ten questions that I have proposed in the introduction. Answering these ten questions will enable anyone to make better judgments about their specimens rather than be reliant on the florid descriptions of those trying to sell their specimens. I think the choice of pictures should mostly be left to those creating the articles with trusted, but liberal monitors to keep things under control in case someone starts to abuse the system. Let the choice of pictures and localities be a perk to those helping to create the articles. I don't anticipate anyone wanting to describe massive ore minerals like chalcocite, but if they do I think we will have to trust the moderators to discourage them or require them to make a pretty strong case as to why it should be interesting enough to include. I was going through a bunch of rubbish from an old collection of Bisbee material the other day and ran across across a couple of really pure chalcocite, cutting grade probably and even put them aside for my systematic collection, but the urge to photograph them and put them in an article in the Best Minerals section did not appear.

I think a star system next to some of the locality entries for the best localities of a particular species is a good idea, but would like the system to be fairly straight forward, easy to apply and easy to understand and not split too many hairs. I would like to hear some suggestions. I have no ideas set in stone about this. But again I think I would leave it to the people creating the articles to add the stars once we sort of all agree on what they mean. Just looking through the rhodochrosite images I think it is pretty plain which are the best localities and which are secondary. When presented with pictures of the best specimens, it should be a lot easier to place the stars. I think that the task will be explaining in simple terms, what the stars mean will be the hard part.

Rock Currier
Crystals not pistols.
avatar Re: Rhodochrosite
March 12, 2009 10:04AM
"Rosenbery" district, Tasmania: this should be spelt: Rosebery. There is a local argument that many of these specimens came from the nearby Rosebery mine, where collecting was rewarded with instant dismissal, but the mineral occurs in both mines.
Some extra info:
A good number of specimens came on the market in the 1970's, and were usually in crusts of rhombohedral crystals to 10mm or so, with a pale pink colour. It is probably calcian, as at Broken Hill, and is typically associated with crystals of quartz and fibrous boulangerite. Kutnahorite also occurs at Rosebery, and is similar in appearance, but paler.
Ralph

Good interesting stuff. I have added it to the article. Rock

Regards,
Ralph



Edited 2 time(s). Last edit at 03/19/2009 09:37AM by Rock Currier.
avatar Re: Rhodochrosite
March 20, 2009 06:41PM
    
Hi Rock,
referring to:
Rhodochrosite
Germany
Reinland-Palatinate, Hunsrück Mts., Waldalgesheim, Elisenhöhe Mine.

Botryoidal rhodochrosite, about 7 cm across © Erik Hock

I think they cheated and took a picture of this specimen while it was wet.

We need someone to tell us about the rhodochrosite specimens from the Elisenhöhe Mine.


I have seen this specimen myself at Erik a few weeks ago - it is quite typical for Dr. Geier mine (synonym of Elisenhöhe and the official name of the last works by Mannesmann - so the locality name should be changed) and maybe a bit too sharpened but the colour and the lustre are overall ok.

The Dr. Geier manganese (and later dolomite) mine has been well known for very nice rhodochrosite specimens ranging in colour from intense pink to brown. The rhodochrosite mostly forms botryoidal aggregates and masses on iron/manganese oxides or ferriferous limestone/dolostone. The most sought after specimens were translucent pink single "balls" or crystal aggregates on lustrous pyrolusite/manganite providing a beautiful contrast.

I just added another picture (and replaced an older one which was too intense in colour):
http://www.mindat.org/photo-219768.html
http://www.mindat.org/photo-14505.html
so there may be more to choose winking smiley

A friend has an excellent specimen from there .. will try to persuade him that i can photograph and post it.

Cheers
Roger
avatar Re: Rhodochrosite
March 21, 2009 02:30AM
Roger,
Thats good input. Do you know about the ten questions that we ideally want to answer for each species/locality?

1. What is the largest crystal of the mineral that the locality has produced?
2. What do the best specimens from this locality look like and where can one be seen?
3. Does the locality produce a variety of different kinds of specimens of this species, and what do the best of each type look like and how many of them were found etc.
4. What are the associated minerals found with this species and what is its geological setting?
5. How abundant are these specimens and when were they found? A type locality? In other words, how rare are they.
6. How do they compare to other specimens of the same mineral from other localities?
7. How much is it worth. This should probably be optional, but in cases where specimens are worth thousands of dollars we should probably say something of the value of these things.
8. What kind of care and feeding do these specimens require? Are they delicate, radioactive, unstable, color changeable etc.?
9. Are the specimens commonly faked, and if so, how to tell if they are?
10. Are there any interesting stories relating to the collecting of these specimens or their discovery as a new mineral?

Ideally what we want to do is to find out the answers to all that stuff and write it up in a a couple of paragraphs and then below put in some stuff about the geology and history of the place. Of course this project that we are working on is one that will never end.

Now you have gotten me cranked up on Rhodochrosite again, and Ill have to go to my slide files and pick out all the good rhodochrosites and scan them in. If I am going to add some of yours, I will probably want to add some of mine too if they are better than hose already in the article.

Rock Currier
Crystals not pistols.
Re: Rhodochrosite
March 21, 2009 03:17AM
Rock,

How is there a chance of more than 100%? LOL.

Dynamite article about one of my favorite minerals, others being: German manganites, Wearsdale fluorites, Chinese scheelites, Romanian (hedgehog) stibnites, Michigan coppers...yada, yada,yada.

Excuse me, I have to empty my drool bucket.

TTFNsmileys with beer(:P)::o(:P)smileys with beer
avatar Re: Rhodochrosite
March 21, 2009 10:55AM
    
Rock,
i will try to find the time to add info for Wolf mine and Dr. Geier subsequently. I hope i can answer the 10 questions winking smiley sufficiently. There is a lot of german literature as well as all the actae at our mining department of the Geological Survey of Rhineland-Palatinate (that´s where i work) and i hope to be able to provide a comprehensive summary/abstract. Any restriction on lenght of the abstract?

Cheers
Roger
avatar Re: Rhodochrosite
March 21, 2009 12:27PM
Roger, what ever you can do will be appreciated. Keep in mind that a lot of the stuff we would like to capture here can be best supplied by the guys who dug it and or bought and sold most of it. The technical stuff is good to, it will help educate those who come here looking for pretty pictures, which we will supply also.

I just scanned in something more than 50 images of rhodochrosite from various localities and hope to get a chance to photoshop and upload them this weekend.

Rock Currier
Crystals not pistols.
Re: Rhodochrosite
March 21, 2009 01:45PM
i havent seen any pics up here from the franklin mining district in newjersey....there were some nice specimens there yes????

Perhaps you are thinking of rhodonite for which Franklin is famous. I did scan on one rhodochrosite from Franklin that is terrific for the locality that Ill stick in just for fun, but it will look pretty terrible compared to the other.
Rock




Edited 1 time(s). Last edit at 03/22/2009 02:01PM by Rock Currier.
avatar Re: Rhodochrosite
March 21, 2009 07:29PM
    
Rock,
ok here we go. I expect you´ll have to "polish" my english a bit as i am no native speaker so feel free to give my text red marks B)

The Dr. Geier mine has been well known for very nice rhodochrosite specimens ranging in colour from intense raspberry pink to brown. The rhodochrosite mostly forms botryoidal aggregates and reniform masses on iron/manganese oxides or ferriferous limestone/dolostone. The most sought after specimens were translucent pink single "balls" or crystal aggregates on lustrous pyrolusite/manganite providing a beautiful contrast. The "balls" mostly have a diameter of a few mm, the largest ones reached about cm size.
Rhodochrosites from Waldalgesheim belong to the best of the species found in Germany. They are mentioned in the same breath as the specimens from Wolf mine, Herdorf and Oberneisen. Most of the rhodochrosite specimens from Dr. Geier mine have been recovered in the Elisenhöhe part of the mine at the so called yellow and green levels. They are comparable to the rhodochrosites from Rothenberg mine, Oberneisen, Heinricherz Mine, Staffel, and Schloßberg Mine, Geisenheim.
Other minerals worth mentioning from the Dr. Geier mine include pyrolusite and manganite crystals up to a few mm lenght as well as brownish pinkish to ivory whitish dolomite crystals up to 1.5 cm. Aragonite crystals as whitish acicular sprays reach 3 cm. Remarkeable is epsomite as up to 10 cm long acicular crystals and aggregates. Epsomite also occurs as crusts, fibrous masses and sometimes ramshorn like formations. The other minerals listed from here are only of local interest. Besides the minerals mentioned above the following species are known: calcite, chalcopyrite, copper, gypsum, "limonite", malachite, pyrite, quartz and romanèchite.

Geology
The iron and manganese ores of the Dr. Geier mine are hosted by Middle Devonian dolostones within an isoclinal through at the southern border of the variscan Rheinisches Schiefergebirge. Genetically they are related to the paleo-karst of the carbonate rocks overlain by marine sands of Oligocene age. Their formation is bound to cavities, caverns, sinkholes and dolines which formed within massive dolomite zones and zones with strong tectonic impact like fractures, joint-sets and bedding planes of the through structure during an uplift-period in the Eocene and the Lower Oligocene.

Up to 50 % of the doline fillings are Tertiary sands and clays. The ores are of mixed iron-manganese type with a Fe: Mn ratio of approx. 2:1. They contain variable amounts of muscovite (10–50%), goethite (30–50%), amorphous Mn oxides (20–30%) and manganite and pyrolusite ("Hartmanganerz", 0–22%). Their formation can be explained by a mixture of descendant colloidal solutions of Fe and Mn hydroxides under oxidizing conditions of the karst hydrography. The Mn and Fe can be deducted from weathered neighboring devonian shales of the Schiefergebirge and the dolomites. The ore grades were 12 – 20 wt.% Mn and averaging 29 wt.% Fe.

History
The oldest reports on manganese mining in the area date from the 17th century. At least since 1808 the Concordia mine near Seibersbach - a few km west of Waldalgesheim - was in operation. In 1832 the Sahler brothers were granted a concession to mine, followed by the Elisenhöhe claim in 1839 and the Waldalgesheim claim in 1840. Contineous mining began in 1880 by the Wandesleben brothers in open cuts. From 1885 Dr. Heinrich Claudius Geier of Mainz started extensive exploration works and sank the first shaft. These activities led to 12 concessions (mining claims) on manganese and iron. In 1904 the Gewerkschaft Braunsteinwerke Dr. Geier was founded and in 1911 all mines and concessions of the Gebr. Wandesleben GmbH (Concordia and Elisenhöhe mines, Waldalgesheim claim) were incorporated. A 7.5 km cableway to the river Rhine was built in 1912 to facilitate the ore transport to the shipping station. 1917 marks the year of the highest Mn ore production (240,853 t). At the same time the construction of the new main shaft was started (Straubenschacht). The ore was used for ironworks and partly as a pigment ore for ceramics. In 1918 673 of 1000 shares of the Gewerkschaft Braunsteinwerke Dr. Geier were acquired by Mannesmannröhren-Werke AG, Düsseldorf, followed by the purchase of another 27 shares in 1926. In 1939 all mining operations were mandated to Mannesmannröhren-Werke AG.
From 1945 to 1950 operations were controlled by the French military government, then management was mandated back to Mannesmann AG. In 1952 the Gewerkschaft Braunsteinwerke Dr. Geier was incorporated into the Gewerkschaft Mannesmann, Düsseldorf. The remaining mines Amalienhöhe, Elisenhöhe and Heerberg were modernized and extended. In the mid of the 1950s the exhaustion of the ore reserves became evident and in 1954 mining of the huge dolomite reserves started. Since 1964 a part of the dolomite was processed to dolomite sinter in rotary furnaces. The products were transported railway-bound via the Rheinstollen gallery to the shipping facility north of Bingen. During these years the mine increasingly suffered from high production costs compared to open pit dolomite mines and finally was not able to compete on the market so in 1971 the mine was closed. In total about 6.4 million tonnes Fe-Mn ore and about 2.5 million tonnes of dolomite had been recovered.

The surface installations of the Straubenschacht site are worth to be specially mentioned. The ensemble is considered to be a most important monument of mining related architecture in Germany. The impressive neo-baroque style site was planned by Markwort & Seibert from Darmstadt. Unfortunately the buildings partly are in a very bad shape today and one can only hope that there will be strong efforts to conserve and restore this outstanding cultural heritage in the near future.

References:
M. Berghäuser (2009): Rhodochrosit und seine Begleitmineralien aus der Grube "Dr.Geier" im Hunsrück. - Lapis, Vol. 34, Nr.3, 13-19.
H. Bottke (1969): Die Eisenmanganerze der Grube Dr. Geier bei Bingen/Rhein als Verwitterungsbildungen des Mangans vom Typ Lindener Mark. - Mineralium Deposita, Vol. 4, Nr 4, 355-367.
O. Ermann (1951): Die Eisen- und Manganerzlagerstätten des östlichen Hunsrücks (im Gebiete von Stromberg-Bingerbrück). - Der Aufschluss, Vol.2, Nr.6, 85-87.
K.Klemp (1987): Grube Dr. Geier - Monument des deutschen Erzbergbaus. - Biebertal, 1987.
W. Rosenberger (1971): Beschreibung rheinland-pfälzischer Bergamtsbezirke. - Vol. 3, Bad Marienberg 1971.
A. Vierschilling (1910): Die Eisen- und Manganerzlagerstätten im Hunsrück und Soonwald. - Z. Prakt. Geol. 18, 393-431.

The 10 holy questions winking smiley:
1. What is the largest crystal of the mineral that the locality has produced?
see 1st paragraph
2. What do the best specimens from this locality look like and where can one be seen?
dito
3. Does the locality produce a variety of different kinds of specimens of this species, and what do the best of each type look like and how many of them were found etc.
dito
4. What are the associated minerals found with this species and what is its geological setting?
see text
5. How abundant are these specimens and when were they found? A type locality? In other words, how rare are they.
no TL, all found during active operation
6. How do they compare to other specimens of the same mineral from other localities?
see text
7. How much is it worth. This should probably be optional, but in cases where specimens are worth thousands of dollars we should probably say something of the value of these things.
They are high-prized because rare on the market
8. What kind of care and feeding do these specimens require? Are they delicate, radioactive, unstable, color changeable etc.?
no special care
9. Are the specimens commonly faked, and if so, how to tell if they are?
no fakes known
10. Are there any interesting stories relating to the collecting of these specimens or their discovery as a new mineral?
nothing published or known to me

Now i am curious what will be the result (:P)

Cheers smileys with beer

Roger



Edited 1 time(s). Last edit at 03/21/2009 09:44PM by Roger Lang.
avatar Re: Rhodochrosite
March 21, 2009 08:25PM
    
Now i saw the complete text in the post ... quite long, isn´t it? Also the other german rhodo localities could be described that way so maybe an extra section for german rhodos like the fluorite procedure??

Just 2 cents

cheers
Roger
avatar Re: Rhodochrosite
March 22, 2009 02:06PM
Roger, Thats good stuff. I suspect that I will include most of it in the article one way or another. There will probably be some red ink and more questions asked. I don't know if I will get around to it this weekend though for I am doing a little quartz project to see if I can figure what to do about quartz. If I can get a handle on quartz, then I think all the others will look easy compared to that. I have been avoiding that monster for too long and it needs to be looked at and some sort of start made on it even though it be feeble.

Rock Currier
Crystals not pistols.
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