Mineralogia, petrografia, geologia

Scientific sections

Mineralogy, Petrography, Geology

DID YOU KNOW...

… in 1794 someone came up with the theory that on the earth's surface there were extraterrestrial objects, which may have fallen from the sky?

In 1772, near Krasnoyarsk (Siberia), the German geologist and zoologist Peter Pallas found and described a huge mass of iron (680 kg) of uncertain origin.

The presence of a massive iron ore was known by some Siberian tribes since the beginning of the 18th century. The giant boulder was said to have fallen from the sky and, therefore, deemed sacred.

In 1794 the physicist Ernst Florens Friedrich Chladni certified the extraterrestrial origin of the material found, which took the name of "pallasite", in honor of Peter Pallas, its first discoverer.

"Drizzle" of stones in Siena

In the dissertation About a drizzle of stones that occurred on the evening of June 16th 1794, the Camaldolese abbot Ambrogio Soldani described a fall of stones in the surroundings of Siena, judging it to be of possible extraterrestrial origin.

Where are those stones stored?

The MRSN houses both Siena and Krasnoyarsk meteorite fragments.

Copertina di "Voyages de M.P.S. Pallas", conservato presso il Museo Regionale di Scienze Naturali di Torino
From Voyages de M.P:S Pallas, Tome IV, Pl. IV, pag 91 – Maradan, Paris, 1793

What are meteorites?

Meteorite (from the Ancient Greek metéōros) = thing high up”: planetary bodies streaking through Earth’s atmosphere and not burning out completely before hitting the Earth's surface.

Most meteorites are fragments of asteroids, shattered by the collision of two celestial bodies orbiting the Sun, mainly within the “asteroid belt” between Mars and Jupiter.

Immagine tratta da "Voyages de M.P.S. Pallas", conservato presso il Museo Regionale di Scienze Naturali di Torino
From Voyages de M.P:S Pallas, Tome IV, Pl. IV, pag 91 – Maradan, Paris, 1793

Do they have scientific relevance?

The finds are of exceptional scientific relevance, as they can make breakthroughs on solar system’s origin. Thus far, over 60,000 meteorites have been classified (half of them found in Antarctica).

Where does their proper noun come from?

The name of each meteorite needs to be clearly distinct from all other meteorite names and abbreviations and must indicate the geographical location of the fall or find.

The name is completed by the date of the fall, if the event was directly observed, or of the find, if it occurred at a later time.

La sezione di Mineralogia, Petrografia e Geologia - dettaglio minerale

How big (or small) are they?

The total weight of the original mass can be anything from a few grams up to over 60 tons (Hoba meteorite, Namibia).

Which is the official classification system?

Meteorites have traditionally been divided into three broad categories, with reference to critical evaluation of elemental composition and morphology:

STONE, IRON, STONY-IRON

  • aeroliths or lithoid meteorites (from litos = stone) or stone: made up of silicate minerals (e.g. olivine, pyroxenes, and plagioclase). They represent just over 95% of all known meteorites;
  • siderites (from sideros = iron) or metallic meteorites or iron: formed almost exclusively of iron-nickel alloys (the two elements in variable proportions). They are about 4% of all known meteorites;
  • siderolites (literally iron stones) or mixed meteorites or stony-iron: made up of mixed parts of iron-nickel metal and silicate minerals. They account for about 0.5% of all known meteorites.

132

geological–lithological collections from the Museum of Geology and Paleontology of the University of Turin: 13.138 samples; 26.884 samples as a total

16.400

specimens make up the mineralogical and petrographic collection, which is constantly being increased by donations and collections made by the Museum staff

800

thin sections of rocks from around the world, collected by Prof. G. Spezia, director of the Museum of Mineralogy and Petrography at the University of Turin, from 1878 to 1911

6.000

samples from the deposit collection

500

samples from the historical collection of rocks and fossils from Sardinia, created by General A. Ferrero della Marmora

What do the section's collections consist of?

The collections include mineral and rock samples, tunnel samples, three-dimensional and plastic models, tools, and mining and lab materials.

Is their history captivating?

The history of the collection of meteorites goes, hand in hand, with the mineral and geological collections, which have been gradually increasing through purchases, bequests, donations, exchanges, and well as collections assembled by scientists and researchers, since 1739 (Establishment of the Turin University museum).

Étienne Borson, first Director of the Museum of Mineralogy of the University of Turin, and Angelo Sismonda, his successor, increased the collections and reorganised the cataloguing, according to a system still in use. Sismonda also made significant acquisitions and oversaw quite a few exchanges with the world-renowned mineralogical museums of the time.

The new director, mineralogist Giorgio Spezia, further developed the endeavours undertaken by his predecessor. By the end of the 19th century, the Royal Mineralogical Museum of Turin, with over 15,000 samples, was one of the most pre-eminent in Europe.

After a rather lengthy stretch of downtime, in 1980 the collection was handed over to MRSN, which progressively acquired another 15,000 mineral samples. The collection currently totals over 65,000 samples, including minerals, rocks, and meteorites.

The mineralogical and geological-lithological collections of the University of Turin

The collection includes 16,547 samples, organised in sections as follows:

Systematic section: it includes topographical and thematic subsections of historical significance and scientific relevance, many of them with exhibit value. The samples from Valchiusella mines (Brosso and Traversella) have gained worldwide recognition both scientifically and aesthetically, whereas the ones from Val d'Ala (Pian della Mussa, Balme, and Ala di Stura) have been studied by Italian and foreign researchers for over two centuries;

Minerals from Vesuvius: resulting from exchanges with the Mineralogy Museum of Naples in the 19th century, later complemented by the collections assembled by Ferruccio Zambonini, director of the Mineralogy Museum of the University of Turin in the early 20th century;

Crystals: partially cut samples, assembled on handmade metal supports, with bases and tags, dating back to the second half of the 19th century;

Gems: assembled on metal supports with 19th-century bases and plates, plus semi-precious and hard stone artefacts;

Meteorites: with world-class samples.

The geological-lithological collection (around 4000 samples partially described in the Catalogue raisonné de la collection mineralogique du Musée d'Historie Naturelle du Turin by Étienne Borson in 1830) is the core of the mineralogical and geological collections. The collections listed below, recently studied both by the Department of Earth Sciences of the University of Turin and the MRSN conservators are of noteworthy historical importance:

  • Minerals and rocks from Egypt: created in the first half of the 19th century (Boreani-Pollonera collection);
  • Mineral and rock samples collected during the expedition of the ship "Stella Polare" (“Polar Star”, 1898 –1900): led by Amedeo of Savoy, Duke of Abruzzi.
Vesuvianite. Elongated and striated prismatic crystal associated with diopside, garnet and chlorite (Pian della Mussa, Balme, Val d'Ala, Turin, Piedmont, Italy)

The meteorite collection

From the 19th century…

The collection was started in 1840, after the fall of a 5 kilos H5 – later named CERESETO – near Casale Monferrato. The meteorite was delivered to Angelo Sismonda, Director of the Museum of the University of Turin, who exchanged some portions of it for fragments of the ORVINIO, HESSLE, STAUNTON, BOHUMILITZ, MILENA, EAGLE STATION, ASSISI, BRAUNAU, FOREST CITY, and WICHITA meteorites.
In the 1886 Meteorite Catalogue, which is stored at the Museum, about fifty of them are recorded. They were acquired through exchanges, purchases, donations or brought to the museum by those who had found them, as it was customary at the time to hand over 'special' finds to the museum.

… to the present day
For quite a while the collection has been accessible to few academics only. Roberto Compagnoni (University of Turin) and Gabriel Iancu (University of Iasi, Romania), have had the merit of bringing some samples to the attention of the scientific community lately.
Since 2007, the collection has undergone a complete overhaul by MRSN staff in order to assess the state of conservation, carry out updated cataloguing, produce photographic documentation of the materials as a whole, and update the classification. The outcome of this work is the Catalogue of Meteorites of the Museum of Mineralogy and Petrography of the University of Turin and the Regional Museum of Natural Sciences, published by the museum in the Catalogues series (XVIII, 2018).

Ten important Italian meteorites
The MRSN houses a collection of ten meteorites that have fallen in Italy: ALESSANDRIA, ALFIANELLO, ASSISI, CERESETO, COLLESCIPOLI, MOTTA DI CONTI, ORVINIO, SIENA, TRENZANO, and VIGARANO. The latter, in particular, provides one of the oldest evidence of the formation of the Solar System.

Astounding find!
During the collection review, an envelope containing fragments of an iron meteorite, which fell in Montemagno (AT) on 17 February 1935, and a sheet with details of the event, reported in newspapers of the time, were found. The material, analyzed by the EDS Electron Microscopy and Microanalysis Laboratory of the Department of Mineralogical and Petrological Sciences of the University of Turin, seems to state that the finding is still unknown to the scientific community.

Oxidized fragments of the meteorite that fell near Montemagno (Asti) on 17 February 1935.
Motta dei Conti meteorite. Olivine chondrite and bronzite fell on 29 February 1868 in Villanova Monferrato (Alessandria).
Carbonaceous chondrite fell in Orgueil (France) on 14 May 1864

The collection of minerals and rocks of Egypt

The collection encompasses 755 samples. The original tags were replaced in the early 1900s, regrettably. The consequent loss of information and the lack of a historical catalogue hampered any further historical-geographical investigation.

The discovery of handwritten fragments inside sacks containing sand samples, bearing a date (January 14th, 1838) and the name of a district (Fazoglo) let figure, through cross-referenced research between the Library of the Museum of Egyptian Antiquities and the State Archive of Turin, the collection was the work of the mining engineer Carlo Boreani and the lawyer Giovanni Pollonera. The two Piedmontese men, who worked in Egypt in the service of the Viceroy Mohammed Ali, took part in the expedition to the Fazoglo district between 1837 and 1839. They were, therefore, working in the places and time in which the collection was created.

Selection of rocks and minerals belonging to the collection from Carlo Boreani's expedition to Egypt.

The rocks and scale models of the University of Turin

Among the 132 geological–lithological collections from the Museum of Geology and Palaeontology of the University of Turin, some have historical value, while others stand out for their scientific relevance, encompassing 13,138 samples (26,884 samples altogether).

The most relevant collections include:

  • samples of both the Frejus and Gotthard rail tunnels and the Mont Blanc motorway tunnel;
  • samples from the Western Alps, collected for over a century and a half by researchers of the Institute of Geological Sciences of the University of Turin;
  • samples of geological phenomena;
  • rocks and fossils from Libya (beginning of the 1900s);
  • rocks from Sardinia (mid-1800s, by General Della Marmora);
  • rocks from Argentera;
  • thin rock sections (over 9,000 slides);
  • geological and geographical models, such as Mont Blanc and the Apuan Alps.

The collection of scale models includes models from the early 1900s, 17 made at the Institute of Geology of the University of Turin in the 60s/70s, 14 small ones made for educational purposes, and 6 white ones (imprint and counter-imprint) depicting the area between Lake Garda and the Brenta Valley, created by Domenico Locchi, from 1916 to 1918.

Most of them are undergoing restoration work. Among the restored pieces, of unique exhibit value is the Apuan Alps scale model, created by Amedeo Aureli in 1913 on the geological surveys of Domenico Zaccagna, geologist and mineralogist, who worked for the Italian Geological Office for over half a century. Copies of the model are housed in other Italian museums.

Geological model of the Apuan Alps. Made by Amedeo Aureli in 1913.

The rock collection of the Fréjus tunnel

The "miracle" of the compressed air drill
The Fréjus railway tunnel (12,234 metres) was completed in thirteen years (1857 – 1870), instead of the expected twenty-five, by using the compressed air drilling machine designed by Giovanni Battista Piatti and optimised by Germano Sommelier.

Extracted rocks entrusted to the most important museums
The tunnel route, that runs in a straight line (except for the last stretch of the French sector Bardonecchia – Modane), was designed according to the evidences provided by the geologist Angelo Sismonda. Copies of the extracted rocks were entrusted to the most renowned naturalistic museums in Europe by Sismonda himself.

All the stones of the petrographic collection
The petrographic collection (570 samples), taken as a geology reference source for the Fréjus motorway tunnel design, consists of sandstones, limestones, dolomitic limestones, dolomites, anhydrides, gypsums, carbonaceous schists, clay schists, calc-schists, chloritoschists, talcoschists, quartzites, and marbles.

Longitudinal profile and general plan of the Frejus Tunnel.

The collection of rocks and fossils of Sardinia

The collection (574 samples) was developed from 1819 onwards by General Alberto Ferrero della Marmora. Copies were given to the Gallery of Mineralogy and Geology in the Jardin des Plantes (Paris), the Museum of Geology in Cagliari and the Museum of Mineralogy in Turin.

The reorganisation after the war
Only 411 specimens were found during the reorganisation of the collection (1985-1990). The others were lost during the bombing of Turin (August 1944), which did not spare Palazzo Carignano, then home to the Museum of Geology.

The collection nowadays
The collection was displayed in exhibitions in Turin, Biella, Cagliari and Monteponi (Iglesias).

Sample of volcanic breccia with the original support from the late 19th century.

The collection of geological phenomena

The collection encompasses over 750 samples representing the extreme macroscopic variability of the materials formed by geological events and processes.

What is a geological phenomenon?
It is the step in a process (physical, chemical, biological, climatic-environmental) which leads to the formation of a rock, not the rock itself. For instance, a sandstone sample is not a geological phenomenon, but whether a peculiar sedimentary structure is plainly visible in that sample, that piece of sandstone represents a geological phenomenon.

New cataloguing method
The geological processes creating distinctly visible structures are volcanism, tectonics, mineralogenesis, karstification, sedimentation, and fossilization. Large folds, intertwined rope lavas, "swamp irons", and cave pearls are definitely eye-catching, thus suitable for displaying purposes.
The multiplicity of possible interpretation emerged during the reorganization of the collection boosted to implement an innovative method of cataloguing the geological phenomena, which is still at the experimental stage.

Calcium schist folded into an “S”. Example of plastic deformation of rocks

The collection of rocks and fossils of Libya

Tripolitania and Cyrenaica…
With the end of the Italo-Turkish war (October 18th, 1912), Turkey relinquished the administrative control over Tripolitania and Cyrenaica, as a consequence of the Italian military occupation. Study campaigns, aimed to point out the geological characterization of those area, were organised and the outcomes presented at the Congress of the Italian Geological Society, held in Tripolitania in 1932.

...in 2300 samples
The paleontological-stratigraphic collection (over 2,300 samples) includes sedimentary rocks, such as calcareous and dolomitic breccias, conglomerates, gravels, sandstones, calcarenites, sands, silts and clays, dolomitic limestones and limestones, oolitic limestones, snails, dolomites, marl, flint and jasper, gypsum, limonite, quartzite, and marly schist.

The mineralogical and geolithological collections

The mineral collections were assembled by integrating those of the University of Turin with samples, of extraordinary aesthetic impact and educational significance, from all over the world.
The section of minerals from the Ossola Valleys and the sub-collection of standard minerals (sixty holotypes and cotypes) stand out for their scientific relevance and completeness.
The MRSN currently holds 16,400 samples.
Among the geological-lithological collections (4,800 samples, 1,600 thin sections), the following are highly significant:

  • collection of ProfessorAlberto Pelloux, mineralogist and petrographer of the University of Genoa, president of the Italian Geological Society in 1934: 500 samples for educational and exposition purposes and 600 thin sections for the study of rocks;
  • collection of 800 thin sections, from all over the world, assembled by prof. Giorgio Spezia, director of the Museum of Mineralogy and Petrography of the University of Turin from 1878 to 1911;
  • collection of 400 slabs of ornamental and building stone materials representing the current Italian manufacturing;
  • collection of "figured stones", as a development of an exhibition held by the museum in 1996: tiny slabs of paesina stones, agates, pierres immaginaires (diorites, trachytes, limestones, sandstones, marbles, quartzites, gneiss, migmatites) with cavern, pinnacles, well, sails, and hilly landscape on the surface;
  • collections of rocks from Valli di Lanzo, Val di Susa, Gran Paradiso, Langhe and Monferrato (Piedmont), acquired through collection campaigns.
Beryl aquamarine variety on muscovite (Pakistan)

The deposits collection

It consists of 4,000 samples from major Italian and international mining districts. In quite a number of cases they reveal the typical stratigraphic sequence: layers of barren rocks, portions of mineralised stones, and superficial alteration of ore deposits.
A database collects any matter regarding geology, geophysical of deposits, history, iconography, and environmental recovery.

From the Lower Paleolithic to the Bronze Age
The video is about Sardinia’s mineral resources exploitation from historical, environmental, geophysical, extractive, and technological perspective.
The time span (100,000 years) made it necessary to split the content into sections:

  • the ice ages of the Palaeolithic: the sea regression turned Sardinia into a landform connected both to other islands (Corsica and Elba) and mainland (Tuscany). Widespread flint and obsidian flakes likely to be found on the surface do testify the geological event;
  • the Neolithic, characterized by the earliest technological advancement (stone tools);
  • the Nuragic civilization, marked out by mineral extraction and metallurgy.

Funtana Raminosa: Sardinia between history and mining
Funtana Raminosa is a thousand-year old mining site that has marked out the destiny of more than one civilization: firstly the Nuragic people, attracted by the eye-catching colour of the Flumendosa river, then the Romans, and lastly the native populations. Despite the closure (1987), the mineralisation process of copper, iron, lead, and zinc is by no means over.

Rosas: past, present, and future
The first part of the video focuses on the geological history of Rosas subsoil: from the Cambrian Period, 500 million years ago, to the long lasting process of turning the sediments into lead, zinc, copper, and iron sulphides deposits.
The second is about the appreciation of the site owing to public funding, the enthusiasm of former miners and young people who have recovered the nineteenth-century wooden wash-house, the excellent state of preservation of quite a few tunnels, and the main processing equipment still in working order.

INSIGHT

Angelo Sismonda

Angelo Sismonda (Corneliano d'Alba, 1807 ~ Turin, 1878) developed a passion for mineralogy by first attending the lectures given by Étienne Borson, chair of mineralogy at the University of Turin, then by Élie de Beaumont and other mineralogists at the Sorbonne, the École des mines and the Muséum d'histoire naturelle, in Paris.

He returned to Turin in 1828, as Borson first offered him the position of assistant and associate professor thereafter. After Borson's passing, he was appointed professor and entrusted with the direction of the Museum of Geology and Mineralogy (1833).

In 1834, during a scientific expedition to the Maritime Alps and the Ligurian Apennines, together with Élie de Beaumont and Ours-Pierre-Armand Dufrénoy, the inspirator and director of the first geological map of France respectively, he came up with the idea of making a similar geological map of Piedmont and Savoy.

In 1846, he was commissioned by King Carlo Alberto to draw up an outline of a geological map of the Sardinian mainland states. The first edition, a review and synthesis of previously published partial surveys, was produced at the behest of the government of Vittorio Emanuele II King of Italy, between 1862 and 1866.

Painted in watercolour on a topographical base from 1857 and mounted on canvas, it was the first official geological map of the newly founded Italian state. A table with 20 boxes and a list of minerals of interest to the mining industry, major lignite, anthracite and gypsum masses, and mineral water sources was annexed.

The metamorphic soils of the Piedmontese Zone (today's calcareous rocks), theretofore thought to be much older (archaeozoic), were believed to belong to the Jurassic period for the first time.

Sismonda was also involved in the Fréjus Tunnel project, regarded as unfeasible due to its length (approximately 12 km), which was instead completed in 1870, twelve years ahead of schedule, by breaking through with a pneumatic drill developed by Germano Sommeiller.

He was awarded membership of the Turin Academy of Sciences, the Accademia Leopoldina, the Italian Society of Sciences, the Pontifical Academy of the New Lincei and the Royal Society of Naples. In 1953, he was appointed dean of the Faculty of Science and director of the School of Pharmacy.

In the last years of his life, he experienced a double bitterness: the questioning of Élie de Beaumont's theory on the origin of mountain ranges (lithogenesis) he had founded his Alpine geological investigations upon (proven wrong by Quintino Sella and Felice Giordano), and the relocation of the Museum of Geology and Mineralogy to Palazzo Carignano, where the multi-level exhibition criterion, which he was a staunch believer in, was abandoned.

None

INFORMATIONS

Massimiliano Senesi,
Mineralogy, Petrography and Geology Department

massimiliano.senesi@regione.piemonte.it.
Tel.: +39 011 4323078

How many things can one learn about the natural world? Find it all out at the Regional Museum of Natural Sciences!