Voudourisite, Cd(SO₄)·H₂O, and lazaridisite, Cd₃(SO₄)₃·8H₂O, two new minerals from the Lavrion Mining District, Greece

Author(s)

Branko Rieck, Christian Lengauer, Gerald Giester

Abstract

Voudourisite, Cd(SO4)·H2O, and lazaridisite, Cd3(SO4)3·8H2O, are two new minerals from the Esperanza Mine, Kaminiza Area, Lavrion Mining District, Greece. This small ancient mine is also the type locality of niedermayrite and katerinopoulosite. Further associated minerals are sphalerite, galena, edwardsite, chalcanthite, gypsum and greenockite. Both secondary minerals form tiny clusters or crusts and are among the latest to form in this paragenetic sequence. They are colourless or white, transparent to translucent, with a white streak and vitreous lustre. No fluorescence is observed. The minerals exhibit conchoidal fracture, no cleavage or preferred parting. The Mohs hardness is ~3 and both have brittle tenacity. Voudourisite is biaxial (–) with refractive indices at 589(1) nm of a = 1.580(2), ß = 1.624(2), ? = 1.640(2), 2Vmeas. = 70(5)°, 2Vcalc.= 61° and ß ~ || [010]. Lazaridisite is biaxial neutral with refractive indices at 589(1) nm of a = 1.552(2), ß = 1.561(2), ? = 1.570(2), 2Vmeas. = 90(5)° and 2Vcalc. = 90°. The chemical compositions of voudourisite and lazaridisite are close to ideal with only minor amounts of copper detectable. The atomic arrangement in voudourisite (space group P21/c with a = 7.633(2), b = 7.458(2), c = 8.151(2) Å, ß = 122.35(1)° and V = 392.0(2) Å3) is related to that of kieserite while lazaridisite (space group C2/c with a = 14.813(3), b = 11.902(2), c = 9.466(2) Å, ß = 97.38(1)° and V = 1655.2(6) Å3) is a distinct structure-type. Calculated densities are 3.838 and 3.088 g/cm3, respectively. The strongest lines in the powder X-ray pattern [d in Å (I) (hkl)] are: 4.890 (66) (110); 3.741 (25) (020); 3.578 (100) (112); 3.230 (43) (200); 2.525 (33) (022); 2.395 (29) (112) for voudourisite and 6.860 (100) (200); 6.317 (72) (111); 5.965 (84) (020); 4.512 (58) (310); 3.727 (78) (202); 3.608(82)(131); 3.109 (83) (402); 3.020 (50) (331) for lazaridisite, respectively.

Organisation(s)

Department of Mineralogy and Crystallography

Journal

Mineralogical Magazine

Volume

83

Pages

551-559

No. of pages

9

ISSN

0026-461X

DOI

https://doi.org/10.1180/mgm.2018.157

Publication date

08-2019

Peer reviewed

Yes

Austrian Fields of Science 2012

105116 Mineralogy, 105113 Crystallography

Keywords

ASJC Scopus subject areas

Geochemistry and Petrology

Portal url

https://ucris.univie.ac.at/portal/en/publications/voudourisite-cdso4h2o-and-lazaridisite-cd3so438h2o-two-new-minerals-from-the-lavrion-mining-district-greece(f0d9dac6-fc9f-40d1-919b-a340832613cf).html