Discussions

💬 Home 🔎 Search 📅 Latest

╳Discussions

💬 Home 🔎 Search 📅 Latest

Groups

Recent Images in Discussions

Mineralogical ClassificationIMA 2003-027 = vurroite

19th May 2005 15:51 UTCMarco E. Ciriotti

• Garavelli, A., Mozgova, N.N., Orlandi, P., Bonaccorsi, E., Pinto, D., Borodaev, Yu.S. (2004): Rare sulfosalts from Vulcano, Aeolian Islands,

Italy. VI. Vurroite, Pb20Sn2(Bi,As)22S54Cl6, a new mineral species. The Canadian Mineralogist, 42, 703-711.

Vurroite, ideally Pb20Sn2(Bi,As)22S54Cl6, 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. Electron-microprobe analyses yield the following ranges of concentrations (wt.%): Pb 39.92–41.80 (ave. 40.92), Bi 27.51–29.11 (ave. 28.30), As 7.59–9.03 (ave. 8.38), Sn 1.33–1.78 (ave. 1.60), Tl 0.00–0.34 (ave. 0.06), S 17.64–8.64 (ave. 18.28), Se 0.09–0.25 (ave. 0.18), Cl 1.74–2.02 (ave. 1.85), Br 0.23–0.25 (ave. 0.24). The empirical chemical formula, calculated on the basis of 44 cations, is Pb18.95Sn1.30(Bi12.99As10.73Tl0.03)Σ23.75(S54.71Se0.22Cl5.00Br0.29)Σ60.22. Single-crystal X-ray-diffraction data reveal a pseudo-orthorhombic symmetry, space group F2mm, with a 45.824(6), b 8.368(2), c 53.990(6) Å, V 20702(6) Å3 and Z = 8. The calculated density is 6.15 g/cm3. The strongest powder-diffraction lines are: 2.07(100)(18.2.8), 3.34(80)(8.2.2), 2.85(80)(16.0.2), 2.69(80)(12.2.6), 2.10(70)(0.4.0), 3.17(60)(18.2.2), 2.17(60)(8.2.6), and 2.04(50)(20.0.12). Vurroite is the second Pb–As–Bi sulfosalt mineral known (kirkiite, Pb10Bi3As3S19, is the other), and it is the first mineral of the system PbS–Bi2S3–As2S3 to contain Cl and Sn. The name of this new mineral species (IMA 2003–027) honors of Filippo Vurro, Professor of mineralogy at the University of Bari, specialist in the mineralogy and geochemistry of modern volcanic deposits.

19th May 2005 15:57 UTCMarco E. Ciriotti

Please read 2005 as year of the publication:

• Garavelli, A., Mozgova, N.N., Orlandi, P., Bonaccorsi, E., Pinto, D., Borodaev, Yu.S. (2005): Rare sulfosalts from Vulcano, Aeolian Islands, Italy. VI. Vurroite, Pb20Sn2(Bi,As)22S54Cl6, a new mineral species. The Canadian Mineralogist, 42, 703-711.

19th May 2005 16:23 UTCMarco E. Ciriotti

And obviously the volume is 43.

1st Jun 2005 11:20 UTCDavid Von Bargen

Added

Mindat.org is an outreach project of the Hudson Institute of Mineralogy, a 501(c)(3) not-for-profit organization.
Copyright © mindat.org and the Hudson Institute of Mineralogy 1993-2024, except where stated. Most political location boundaries are © OpenStreetMap contributors. Mindat.org relies on the contributions of thousands of members and supporters. Founded in 2000 by Jolyon Ralph.
Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: April 26, 2024 13:04:41

Go to top of page