TY - JOUR

T1 - Zoisite-(Pb), a New Orthorhombic Epidote-Related Mineral from the Jakobsberg Mine, Värmland, Sweden, and Its Relationships with Hancockite

AU - Perchiazzi, Natale

AU - Mauro, Daniela

AU - Vignola, Pietro

AU - Zaccarini, Federica

AU - Eldjarn, Knut

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/12/30

Y1 - 2021/12/30

N2 - The new mineral zoisite-(Pb), ideally CaPbAl 3 (SiO 4)(Si 2 O 7)O(OH), was discovered in a sample from the Jakobsberg manganese-iron oxide deposit, Värmland, Sweden. Zoisite-(Pb) is found as pale pink subhedral prisms elongated on [010], up to 0.3 mm in size, associated with calcite, celsian, diopside, grossular, hancockite, hyalophane, native lead, phlogopite, and vesuvianite. Associated feldspars show one of the highest PbO contents (~7–8 wt%) found in nature. Electron-microprobe analysis of zoisite-(Pb) point to the empirical formula (Ca 1.09 Pb 0.86 Mn 2+ 0.01Na 0.01) ∑1.97 (Al 2.88 Fe 3+ 0.10 Mn 3+ 0.04) ∑3.02 Si 3.00 O 12 (OH) 1.00 . The eight strongest diffraction lines [d obs, I obs, (hkl)] are 8.63 s (101), 8.11 mw (200), 4.895 m (011), 4.210 m (211), 3.660 s (112, 311), 3.097 mw (312), 2.900 s (013), and 2.725 m (511). Zoisite-(Pb) is isostructural with zoisite and its crystal structure was refined up to R 1 = 0.0213 for 2013 reflections with F o > 4σ(F o). Pb shows a stereochemically active lone pair leading to a lopsided distribution of its coordinating oxygens. A full chemical and Raman characterization of zoisite-(Pb) and of the Pb-bearing epidote hancockite is reported, together with an improved crystal structural model of hancockite, refined up to R 1 = 0.0254 for 2041 reflections with F o > 4σ(F o). The effects of the incorporation of Pb in the crystal structure of zoisite-(Pb), hancockite, and related synthetic and natural phases are described and discussed.

AB - The new mineral zoisite-(Pb), ideally CaPbAl 3 (SiO 4)(Si 2 O 7)O(OH), was discovered in a sample from the Jakobsberg manganese-iron oxide deposit, Värmland, Sweden. Zoisite-(Pb) is found as pale pink subhedral prisms elongated on [010], up to 0.3 mm in size, associated with calcite, celsian, diopside, grossular, hancockite, hyalophane, native lead, phlogopite, and vesuvianite. Associated feldspars show one of the highest PbO contents (~7–8 wt%) found in nature. Electron-microprobe analysis of zoisite-(Pb) point to the empirical formula (Ca 1.09 Pb 0.86 Mn 2+ 0.01Na 0.01) ∑1.97 (Al 2.88 Fe 3+ 0.10 Mn 3+ 0.04) ∑3.02 Si 3.00 O 12 (OH) 1.00 . The eight strongest diffraction lines [d obs, I obs, (hkl)] are 8.63 s (101), 8.11 mw (200), 4.895 m (011), 4.210 m (211), 3.660 s (112, 311), 3.097 mw (312), 2.900 s (013), and 2.725 m (511). Zoisite-(Pb) is isostructural with zoisite and its crystal structure was refined up to R 1 = 0.0213 for 2013 reflections with F o > 4σ(F o). Pb shows a stereochemically active lone pair leading to a lopsided distribution of its coordinating oxygens. A full chemical and Raman characterization of zoisite-(Pb) and of the Pb-bearing epidote hancockite is reported, together with an improved crystal structural model of hancockite, refined up to R 1 = 0.0254 for 2041 reflections with F o > 4σ(F o). The effects of the incorporation of Pb in the crystal structure of zoisite-(Pb), hancockite, and related synthetic and natural phases are described and discussed.

UR - http://www.scopus.com/inward/record.url?scp=85121874971&partnerID=8YFLogxK

U2 - 10.3390/min12010051

DO - 10.3390/min12010051

M3 - Article

VL - 12.2022

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 51

ER -