RARE SULFOSALTS FROM VULCANO, AEOLIAN ISLANDS, ITALY. VI. VURROITE, Pb20Sn2(Bi,As)22S54Cl6, A NEW MINERAL SPECIES

Abstract

Vurroite, ideally Pb 20 Sn 2 (Bi,As) 22 S 54 Cl 6, is a new mineral species from the modern Pb-Bi epithermal deposit of La Fossa crater, on Vulcano Island, Italy. It occurs as a volcanic encrustation deposited around high-temperature fumaroles (400-600°C) located both on the rim and on the inner slope of the active crater. The mineral consists of slender, needle-shaped crystals up to 0.4 mm long and 0.01 mm across, which generally form fibrous aggregates. Associated minerals are bismuthinite, lillianite, kirkiite, heyrovskýite, galena, and other less-well-characterized sulfochlorides of Pb(Bi), some of which contain traces of Tl, Sn or As. The color of vurroite is silver-gray, with a metallic luster. In reflected plane-polarized light, it is white, without distinct bireflectance or pleochroism. Anisotropism is weak, without color effects. The measured values of reflectance in air for a single grain are 34.25 (470 nm), 32.95 (546 nm), 32.60 (589 nm), 31.05% (650 nm); values for 400-800 nm are tabulated. Electronmicroprobe analyses yield the following ranges of concentrations (wt.%):

First occurrence of iodine in natural sulfosalts: The case of mutnovskite, Pb2AsS3(I,Cl,Br), a new mineral from the Mutnovsky volcano, Kamchatka Peninsula, Russian Federation

“…The Cd-bearing sulfosalts kudriavite and Cd-cannizzarite and Pb-Bi-As sulfosalts occur at intermediate temperature values. This evidence is in contrast with the condition of deposition observed in the actual epithermal deposit of the La Fossa crater of Vulcano, Aeolian Islands, Italy (Garavelli et al 2005;Borodaev et al 2003). This latter deposit is characterized by a sulfosalt assemblage which is very similar to that occurring at the Mutnovsky volcano, but no relevant paragenetic sequence of deposition could be observed.…”

“…The presence of Cl is well known among natural halogen-bearing sulfosalts (ardaite, Pb 10 Sb 6 S 17 Cl 4 = Breskovska et al 1982;dadsonite, Pb 23 Sb 25 S 60 Cl = Moëlo 1979; pillaite, Pb 9 Sb 10 S 23 ClO 0.5 = Orlandi et al 2001; pellouxite, (Cu,Ag) 2 Pb 21 Sb 23 S 55 ClO = Orlandi et al 2004; vurroite, Pb 20 Sn 2 (Bi,As) 22 S 54 Cl 6 = Garavelli et al 2005). Less usual is the presence of minor Br substituting for Cl, which has only been reported in the recently approved halogen-sulfosalt vurroite (Garavelli et al 2005). The most interesting feature is the presence of iodine in mutnovskite.…”

“…Mutnovskite contains traces of Se (up to 1.33 wt%); the presence of this element is ascribed to the high Se content of the fl uids discharging from the fumarole vents and it is a common feature of sulfosalts deposited in contemporary epithermal deposits connected to active volcanoes (Borodaev et al 1998;Vurro et al 1999;Borodaev et al 2000Borodaev et al , 2001Borodaev et al , 2003Garavelli et al 2005). …”

210Pb and 210Po in Geological and Related Anthropogenic Materials: Implications for Their Mineralogical Distribution in Base Metal Ores

“…[60,61]). Several of sulphosalts, including Cl-and Br-bearing species (e.g., vurroite [62]) have been first described from the locality.…”

BRONTESITE, (NH4)3PbCl5, A NEW PRODUCT OF FUMAROLIC ACTIVITY FROM LA FOSSA CRATER, VULCANO, AEOLIAN ISLANDS, ITALY

“…In the last few years, a renewed mineralogical interest in the fumarole system at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy has led to the discovery of a number of rare and new minerals [for details, see for instance Garavelli et al (2005), Campostrini et al (2008), Demartin et al (2009), Mitolo et al (2009), and references therein]. During a systematic sampling carried out in the years 2007-2008, the new species brontesite (NH 4 ) 3 PbCl 5 , an ammonium lead chloride, was also discovered.…”