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New arsenate minerals from the Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia; II, Ericlaxmanite and kozyrevskite, two natural modifications of Cu (sub 4) O(AsO (sub 4) ) (sub 2)

I. V. Pekov, N. V. Zubkova, V. O. Yapaskurt, D. I. Belakovskiy, M. F. Vigasina, E. G. Sidorov and D. Yu. Pushcharovsky
New arsenate minerals from the Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia; II, Ericlaxmanite and kozyrevskite, two natural modifications of Cu (sub 4) O(AsO (sub 4) ) (sub 2)
Mineralogical Magazine (December 2014) 78 (7): 1553-1569

Abstract

Two new minerals, ericlaxmanite and kozyrevskite, dimorphs of Cu (sub 4) O(AsO (sub 4) ) (sub 2) , were found in sublimates of the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. They are associated with each other and with urusovite, lammerite, lammerite-beta , popovite, alarsite, tenorite, hematite, aphthitalite, langbeinite, As-bearing orthoclase, etc. Ericlaxmanite occurs as tabular, lamellar, equant or short prismatic crystals up to 0.1 mm in size, their clusters and pseudomorphs after urusovite crystal crusts up to 1.5 cmX2 cm in area. Kozyrevskite occurs as prismatic crystals up to 0.3 mm long in clusters and as individual crystals. Both minerals are transparent with a vitreous lustre. They are brittle, with Mohs' hardness approximately 31/2. Ericlaxmanite is green to dark green. Kozyrevskite is bright grass green to light yellowish green; D (sub calc) is 5.036 (ericlaxmanite) and 4.934 (kozyrevskite) g cm (super -3) . Both minerals are optically biaxial (-); ericlaxmanite: alpha = 1.870(10), beta = 1.900(10), gamma = 1.915(10), 2V (sub meas) = 60(15) degrees ; kozyrevskite: alpha = 1.885(8), beta = 1.895(8), gamma = 1.900(8), 2V (sub meas.) = 75(10) degrees . The Raman spectra are given. Chemical data (wt.%, electron microprobe; the first value is for ericlaxmanite, the second for kozyrevskite): CuO 57.55, 58.06; ZnO 0.90, 1.04; Fe (sub 2) O (sub 3) 0.26, 0.12; SiO (sub 2) n.d., 0.12; P (sub 2) O (sub 5) 0.23, 1.23; V (sub 2) O (sub 5) 0.14, 0.37; As (sub 2) O (sub 5) 40.57, 38.78; SO (sub 3) 0.17, 0.43; total 99.82, 100.15. The empirical formulae, based on 9 O a.p.f.u., are: ericlaxmanite: (Cu (sub 3.97) Zn (sub 0.06) Fe (sub 0.02) ) (sub Sigma 4.05) (As (sub 1.94) P (sub 0.02) V (sub 0.01) S (sub 0. 01) ) (sub Sigma 1.98) O (sub 9) and kozyrevskite: (Cu (sub 3.95) Zn (sub 0.07) Fe (sub 0.01) ) (sub Sigma 4.03) (As (sub 1.83) P (sub 0.09) S (sub 0.03) V (sub 0. 02) Si (sub 0.01) ) (sub Sigma 1.98) O (sub 9) . Ericlaxmanite is triclinic, P1I, a = 6.4271(4), b = 7.6585(4), c = 8.2249(3) Aa, alpha = 98.396(4), beta = 112.420(5), gamma = 98.397(5) degrees , V = 361.11(3) Aa (super 3) and Z = 2. Kozyrevskite is orthorhombic, Pnma, a = 8.2581(4), b = 6.4026(4), c = 13.8047(12) Aa, V = 729.90(9) Aa (super 3) and Z = 4. The strongest reflections in the X-ray powder patterns [d Aa(I)(hkl)] are: ericlaxmanite: 3.868(46)(101), 3.685(100)(020), 3.063(71)(012), 2.957(58)(02I2), 2.777(98)(2I12, 2I1I1), 2.698(46)(2I1I2) and 2.201(51)(013, 031); kozyrevskite: 3.455(100)(004), 3.194(72)(020, 104), 2.910(69)(022), 2.732(82)(122), 2.712(87)(301) and 2.509(92)(123). Their crystal structures, solved from single-crystal X-ray diffraction data [R = 0.0358 (ericlaxmanite) and 0.1049 (kozyrevskite)], are quite different. The ericlaxmanite structure is based on an interrupted framework built by edge- and corner-sharing Cu-centred, distorted tetragonal pyramids, trigonal bipyramids and octahedra. The kozyrevskite structure is based on complicated ribbons of Cu-centred distorted tetragonal pyramids and trigonal bipyramids. Ericlaxmanite is named in honour of the Russian mineralogist, geologist, geographer, biologist and chemist Eric Laxman (1737-1796). Kozyrevskite is named in honour of the Russian geographer, traveller and military man Ivan Petrovich Kozyrevskiy (1680-1734), one of the first researchers of Kamchatka.


ISSN: 0026-461X
EISSN: 1471-8022
Coden: MNLMBB
Serial Title: Mineralogical Magazine
Serial Volume: 78
Serial Issue: 7
Title: New arsenate minerals from the Arsenatnaya fumarole, Tolbachik Volcano, Kamchatka, Russia; II, Ericlaxmanite and kozyrevskite, two natural modifications of Cu (sub 4) O(AsO (sub 4) ) (sub 2)
Affiliation: Moscow State University, Geology Department, Moscow, Russian Federation
Pages: 1553-1569
Published: 201412
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 11
Accession Number: 2015-024191
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 8 tables
N55°49'02" - N55°49'02", E160°22'02" - E160°22'02"
Secondary Affiliation: Russian Academy of Sciences, Fersman Mineralogical Museum, RUS, Russian FederationRussian Academy of Sciences, Institute of Volcanology and Seismology, RUS, Russian Federation
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201512
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