Minerals from Alps

Per la versione italiana clicca qui

 

 

The Alps are a mountain chain situated in the south of Europe. In particular most of Austria, Switzerland and Slovene are formed by the alpine valleys. The western part of the mountains is divided between Italy and France. Italy is the only country where the alpine chain is completely developed, from west to east.

The alpine landscape is characterized by very high mountains and peaks, large valleys and narrow canyons, large glaciers above the highest parts of the mountains.MVC-389F.jpg (25762 byte)

These mountains have been for a long time an obstacle to the free circulation among the people and the different countries . Due to this reason the cultures in the different valleys are extremely differentiated as languages, religions, uses than till now is possible to see and evaluate . In the Alps we have different languages, as italian, german, french, eastern languages. More than this we have also some "ancient" languages like ladin, directly derived from latin.

The minerals from this region are very often of extraordinary beauty and very attractive. The mineral collectionism is very widespread and has very ancient traditions . Till now is possible to visit private collections generally of aesthetic/systematic kind generally constituted by systematic collections of alpine minerals or of a certain region of the Alps: some of these collections has samples that are even better than the best samples of the main museums!!

Very often these collections have been developed through different generations, from father to son.

Clearly the regions where the mineral collecting was more developed, are also the main regions where till now is possible to find the best mineral samples, in particular

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  1. Bianco mountain and high Savoy, it is the area between Italy and France. Very attractive from this area are the smoky quartz’s and the pink fluorites.
  2. San Gottardo: this area is completely in Swiss territory , from the northern part of the ticino region and the uri region .In this area we have the san Gottardo mountain, The Bedretto valley, the Furka pass. The variety of alpine minerals coming from this area is very large , from smoky quartz to anatases, but might be the most famous mineral are the iron roses, aggregates of extremely bright hematite’s.
  3. Alto Adige: this region is in the extreme north of Italy, at the border with Austria and is very famous for its fantastic alpine mineralisations. In particular we can remember the green titanites, of gemmy quality , the apatites the pericline and the euclase of Aurina valley, Vizze Valley, and the garnets from Rombo pass.
  4. Malenco valley : is a large valley with confluence in the Valtellina valley . From this area there were some asbestos mines, where some outstanding demantoide samples have been found, probably the best in the world. From this valley we have also very nice and large samples of Perowskite and Artinite,
  5. Formazza and Binn valleys : these areas are very famous for the crystallisations of Cervandone area and Devero , with fantastic iron roses and cafarsites. The Binn valley is extremely famous for the Lengebach quarry with solfo salts in beautiful crystallization’s in the white dolomite.
  6. Zillertall and Tauri regions: in practice all the southern part of Austria close to the border with Italy. Very numerous the localities that gave fantastic alpine samples, we can remember Berliner hutte in Zillertal , with scepter amethyst , iron roses, apatites, Habactal with emeralds, Knappenwaden very famous for the epidotes, probably the best in the world together with the Alaskan ones, Ferbetal with green titanites,

 

Occurrence and paragenetic classification of Alpine minerals

 

The Alpine area is very famous for its minerals and there are many different paragenetic groups of minerals related to different types of rocks and formations. To give an idea of what means the alpine region in terms of mineralogy, we can remember that more than 800 different species have been found in the alpine region. argientiere glacier

The alpine region gave the name to a lot of different minerals, most of them very easily collectable some time ago and now not so much common. Regarding the italian regions, we can remember the Dolomite, from the dolomites, mountains in the NE of Italy, Fassaite, from Val di Fassa, a valley in the Dolomite region, Bavenite, from Baveno, a famous quarry of granites in the central part of the Alps, Canavesite, from Canavese, a region in the north west of Italy and a lot of other minerals.

This fact is a clear signal that the alpine region is very rich of minerals in terms of quantities and qualities.

To say the truth the alpine region WAS very rich of minerals. At this time most of the quarries and mines are closed due to the uneconomicity of most of the ores and to the high cost of the man power, compared with other countries.

In addition to this, at least in Italy, a savage local regulation prohibits most of the research localities in name of not well defined environmental reasons. The reality is , at least in case of the minerals, that these jewels of the nature don’t resist in natural conditions. In addition to this we have to remember that only with activities of research normally we can have always new minerals. Each good collector and rockhounder knows that only in localities with an active extractive activity, artificial ( mines, quarries, excavations for roads, tunnels, et. ) or natural ( slides, rock falls, glaciers, etc. ) is possible to find good samples.

We hope that in Italy the authorities will take a more open minded policy in terms of regulation of the search activity and not a generalized prohibition.

Going back to our minerals and their occurrences, we have different occurrences of the minerals in the Alps: just knowing the geology and the formations, we can forecast which kind of minerals we can find in the area.

The most known and rich occurrences of minerals of the Alps are:

ALPINE FISSURES

This is the most known kind of occurrence of alpine minerals.

The alpine fissures are simply discontinuities or small veins, generally totally or partially open, completely covered in all sides of very nice crystals. Most of the time also internally to the veins we have a lot of loose minerals or aggregates, floaters, etc.

These fissures are generally completely filled with mud and is particularly "thrilling" to open one of these fissures, since most of the minerals are loose inside the vein and you extract the minerals with the hands, without any hammer od other tools. On the contrary, there is a lot of specific tools to find and exploit these veins, the most famous is a sort of iron bar that is used to test the vein, to see if it continues internally and if it is open.Photo from the Chamonix mineral group site

The alpine fissures were formed in the latest phases of the alpine orogenesis and are related to the stress fields of the orogenesis. During these phases, at high temperature and pressures, solutions extremely rich of dissolved salts circulated and deposited generally internally to the fissures the minerals. One characteristic of these fissures is that they generally occur in schistose rocks and are oriented perpendicularly to the schistosity. This is the reason why normally you can find the already discovered fissures open and with the minerals covering the sides: it is in practice impossible to extract pieces of a certain dimension of minerals from the walls of the fissure due to the schistosity of the rock. .

 

Photo from the Chamonix Mineral Group website

The dimension of these fissures are from few centimeters to a maximum of 20-30 meters of length. The dimensions of the crystal are various, anyway the most common mineral is the quartz, found in crystals of more than one meter and of the weight of more than 7 quintals.

There is a lot of regions famous for the minerals in fissures . Among these we can remember the Gottardo region in Switzerland, different valleys in the Uri region in Switzerland, Bourg d’Oissans, in France, Val Aurina and Val di Vizze in Italy, Zillertal region in Austria, etc.

The minerals that you can find are very numerous. Among these the most known and aesthetic is the quartz.

The extraction of particularly bright crystals of quartz for these veins is an organized activity since the most remote times. One of the first testification we have about these activities is from Plinio il Vecchio, who in the first century after Christ described the activities of some families or clans extracting the minerals in the alpine valleys.

The different occurrences of fissures are in schistose rocks and in igneous of metamorphic derived rocks.

The fissures of the Monte Bianco region are very famous for their fantastic quartz crystals and pink fluorites. Fluorite- Argienteire Gf Charlet coll.

The most common paragenesis in this case is with quartz, albite and adularia.

A lot of different accessories minerals are then present. Among these the most famous and aesthetic are: fluorite, generally pink, hematite, in extremely bright crystals in aggregates of the rose shape, Titanite in all the colors, the most famous are the green titanites, transparent and of gemmy quality, bissolite, anatase and rutile.

If the fissures are very famous and widespread in the central alpine region, in the southern Alps generally the mineral occurrence is in geodes more than fissures. One of the difference between fissures and geodes in clearly the shape, the other one is the timing of formation of the mineralisations : the fissures are mineralized in a second phase, when the rocks were already formed, the geodes are formed in the late stage of crystallization of the rock.

The most famous area for its geodes id the Baveno area, very famous for its orthoclase crystals, with much accessories.

Among them Bavenite, zinnwaldite, gadolinite, etc.

METAMORPHIC CARBONATES

In different localities of the Alps, there are masses of carbonates more or less metamorphosed, both dolostones and limestones.

The most famous locality is the Binn valley, with the very famous dolostones with crystalizations of solphosalts . In addition we have rutile, tourmalines, realgar, etc., in very nice cristallisations extremely showy on the white matrix. In Italy a very famous locality is the marble quarry of Crevola d’Ossola, from which was extracted the marble of the Milan dome.

Another occurrence of minerals in the carbonate rocks is in the carbonatic masses thermo metamorphosed by the intrusion of igneous or volcanic rocks.

The most famous localities are in the Dolomite area, in Italy, particularly in the Fassa Valley , in the Fiemme valley, where Triassic rocks have been metamorphosed by vulcanite’s and the southern part of the Adamello intrusion, a plutonic intrusion that metamorphosed the calcareous rocks in the south ( see article …)

Typical minerals in these rocks are vesuvianite , garnets ( grossular ), fassaite, uralite, epidote, xantofillite, spinello, zoisite, monticellite, gehlenite.

SERPENTINE

The serpentine is a green rock very diffused in the Alps and with some crystallisations extremely interesting from the aesthetic point of view.

Typical mineral is first of all the asbestos, exploited from the industrial point of view in a huge quarry in Balangero .

Some mines and quarries of asbestos were active in the Val Malenco area. In these quarries several years later were found spectacular crystals of Demantoide of gemmy quality.

A rock in small veins in serpentine is the rodingite, in which there are fissures with spectacular crystallization’s: garnet, grossularia and andradite, vesuvianite, diopside, epidotes, chlorite, zoisite, apatite, titanite, magnetite.

Finally, a typical mineral of these rocks is the perowskite, in crystals of more than 1-2 centimeters.

 

Here below you can find in more details some of the most important areas from the mineralogical point of view ( in Italy ) . 

  1. Aurina Valley (It)

  2.  

  3. Epidote in Varaita Valley (It-Fr)

  4. Baveno Quarries (It)

  5. Mont Blanc and his Minerals (It-Fr-Ch)

  6. Minerals from Cervandone Mountain (It-Ch)

  7. Tavetsch Valley (Ch)

 

( by Carlo & Bepy)

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