VESUVIUS

History

Mineral species of Vesuvius described for the first time

References

In the history of Mineralogy, Vesuvius is by far the most important volcano: it used to be the only accessible one to the fathers of Mineralogy during the XVIIIth and XIXth centuries; thus, not only it was the source of rare and exceptionally beautiful minerals, but it created the conditions for development of theories on mineral genesis. Furthermore, theoretical and practical Volcanology was actually born here, having Vesuvius been the seat of the first volcanological observatory (1845) in the world, to which for almost half a century any geologist would go.

 

History

The very first mineralogical interest for Vesuvius dates back not so much as to 1631 (i.e., the subplinian eruption occurred after four centuries which opened the conduit to an activity stage which lasted till 1944), rather as 1709-1716 (beginning of archeological excavations at Herculaneum) and even 1738-1763 (excavations at Pompaeii). The first descriptions of Vesuvius mineral and rocks are due to G.M. Della Torre (1755) and F. Galiani (1772). J. Ferber (1773) was the the first who distinguished minerals on the basis of their environment in: (a) ejecta, (b) lavas and (c) fire (i.e., in fumeroles). The first studies on crystal morphology are by J.B. Romé de lIsle (1783) and R.J. Haüy (1801). Further systematic descriptions are by G. Gioeni (1791), J.C. Delamétherie (1797) and S. Breislak (1801). Among the great mineralogists who operated at Vesuvius, let us remind T. Monticelli, N. Covelli, A. Scacchi, M. Melloni, G. Mercalli, G. vom Rath diring the XIXth century, and A. Lacroix, F. Zambonini. G. Carobbi and A. Rittman during the first half of the current century.

Mineral findings in relation to their formation environment. Throughout the Somma-Vesuvius volcanic complex more than 185 mineral species have been identified, among which 49 new ones. Furthermore, essential mineral data for some 30 species were determined on samples from here.

Minerals occur in four main types of environment:

 

  1. in metamorphosed calcareous ejecta (especially on the outer slope of Mt. Somma), to be further distinguished in three sub-types:
    1. massive ejecta, with anhedral crystals scattered as patches and clots throughout the calcite matrix: humite, periclase (brucite), lapislazuli, biotite, pyroxenes, magnetite, galena, sfalerite;
    2. vacuolated ejecta, pierced by geods having a radiated-concentric texture consisting of a calcite+augite rim, a biotite+calcite+olivine intermediate zone, and an inner void letting crystals to grow free: wollastonite, humite and feldspathoids;
    3. silicated vacuolar ejecta, with the same texture as 1b, but lacking calcite, which is being replaced by calc-silicate minerals.

     

  2. in the cracks and fissures of the lava blocks. At Vesuvius the main minerals are pyroxenes, amphiboles, feldspathoids, fayalite, vonsenite, hausmannite, cuprite, hematite, sellaite, fluorite, and anhydrite; at Mt. Somma besides the same minerals there are numerous zeolites.

    3.  

  3. in the fumaroles, which are still active at Vesuvius while being fossiles at Mt. Somma: silvite, halite, chlorocalcite, lawrencite, bararite, chlormanganokalite, atacamite, cotunnite, calchocyanite, thenardite, mascagnite, palmierite, antlerite, euchlorine, alunite, voltaite, bassanite, matteuccite, covellite, millerite, galena, pyrite, tenorite.

    4.  

  4. in the tephritic and phonolitic lavas and pyroclastic rocks, as fenocrysts: leucite, sanidine.Museums. Most and best Vesuvius minerals are on display at Mineralogical Museum of Naples University, where a number of Scacchi's and Zambonini's holotypes are preserved. The Museum itself (founded 1801) is a masterpiece of cabinet work in the Empire stile.

 

Mineral species of Vesuvius described for the first time

Oxydes: tenorite (G. Semmola, 1825), periclase (A. Scacchi, 1841), magnesioferrite (C.F. Rammelsberg, 1859), lime (A. Scacchi, 1883);

Halogenides: molysite (J.F.L. Hausmann, 1819), cotunnite (T. Monticelli & N. Covelli, 1825), silvite (F.S. Beudant, 1832), kremersite (P. Kremers, 1851), scacchite (J.N. Adam, 1869), melanothallite (A. Scacchi, 1870), chlorocalcite (A. Scacchi, 1872), erythrosiderite (A. Scacchi, 1872), chloraluminite (A. Scacchi, 1873), chloromagnesite (A. Scacchi, 1873), cryptohalite (A. Scacchi, 1873), pseudocotunnite (A. Scacchi, 1873), eriochalcite (A. Scacchi, 1884), chlormanganokalite (H.J. Johnston-Lavis, 1906), mitscherlichite (F. Zambonini & G. Carobbi, 1925), avogadrite (F. Zambonini, 1926), malladrite (F. Zambonini & G. Carobbi, 1926), ferruccite (G. Carobbi, 1933), carobbiite (H. Strunz, 1956)

Solfates: aphthitalite (G. Thomson, 1795), cyanochroite (A. Scacchi, 1855), picromerite (A. Scacchi, 1855), chlorothionite (A. Scacchi, 1872), dolerofanite (A. Scacchi, 1873), chalcocyanite (A. Scacchi, 1873), euchlorine (F. Pisani, 1875), palmierite (A. Lacroix, 1907), bassanite (F. Zambonini, 1910), manganolangbeinite (F. Zambonini & G. Carobbi, 1924), mercallite (G. Carobbi, 1935), matteuccite (G. Carobbi & C. Cipriani, 1952)

Silicates: leucite (A.G. Werner, 1791), vesuvianite (A.G. Werner, 1795), meionite (R.J. Haüy, 1801), nepheline (R.J. Haüy, 1801), haüyne (Bruun- Neergaard, 1807), sarcolite (G. Thomson, 1807), humite (C. de Bournon, 1817), anorthite (G. Rose, 1823), forsterite (M. Lévy, 1824), davyne (T. Monticelli & N. Covelli, 1825), monticellite (H.G. Brooke, 1831), microsommite (A. Scacchi, 1872), clinohumite (A. Des Cloizeaux, 1876), cuspidine (A. Scacchi, 1876), litidionite (E. Scacchi, 1880), kaliophilite (B. Mierisch, 1886), cuprorivaite (C. Minguzzi, 1938), panunzite (E. Benedetti et al., 1977), potassium-fluor- richterite (Della Ventura et al., 1983), montesommaite (R.C. Rouse et al., 1990), quadridavyne (E. Bonaccorsi et al., 1994).

Potential findings. Although within a national park and with high hazard possibilities, the Vesuvius slopes are undergoing a wild anthropisation: reduction of access due to privatization and construction, from one side, and random excavation followed by concrete pouring, from the other side. Finding minerals, especially as good samples, is increasingly difficult: it is mainly occasional and related to quarry works, both on Mt. Somma outer (NW) slope (Cupa, S. Vito, Pollena) and on Vesuvius S and SE slopes (Villa Inglese, Boscotrecase). The first localities provide ejecta, the last ones cracks on lavas. Fumeroles are poorly producing, since they are now cold, the last eruption having occurred in 1944.

 

References

M. Carati (1982) Guida alla mineralogia vesuviana. Bologna, Calderini.F. Zambonini (1935) Mineralogia vesuviana (2th ed. by E. Quercigh). Napoli, Acc. Sc. Fis. Mat.