Lavinskyite, K(LiCu)Cu6(Si4O11) 2(OH)4, isotypic with plancheite, a new mineral from the Wessels mine, Kalahari Manganese Fields, South Africa

Hexiong Yang; Robert T. Downs; Stanley H. Evans; William W. Pinch

doi:10.1515/am.2014.4601

Lavinskyite, K(LiCu)Cu₆(Si₄O₁₁) ₂(OH)₄, isotypic with plancheite, a new mineral from the Wessels mine, Kalahari Manganese Fields, South Africa

Hexiong Yang
, Robert T. Downs
, Stanley H. Evans
, William W. Pinch

Geosciences

Research output: Contribution to journal › Article › peer-review

8 Scopus citations

Abstract

A new mineral species, lavinskyite, ideally K(LiCu²⁺)Cu ₆²⁺(Si₄O₁₁)₂(OH) ₄ (IMA 2012-028), has been found in the Wessels mine, Kalahari Manganese Fields, Northern Cape Province, South Africa. Associated minerals include wesselsite, pectolite, richterite, sugilite, and scottyite. Lavinskyite crystals are tabular [parallel to (010)]. The mineral is light blue, transparent with very pale blue streak and vitreous luster. It is brittle and has a Mohs hardness of 5; cleavage is perfect on {010} and no parting was observed. The measured and calculated densities are 3.61(3) and 3.62 g/cm³, respectively. Optically, lavinskyite is biaxial (+), with α = 1.675(1), β = 1.686(1), γ = 1.715(1), 2V_meas = 64(2) . An electron microprobe analysis produced an average composition (wt%) of SiO₂ 42.85(10), CuO 46.13(23), K₂O 4.16(2), MgO 1.53(17), Na₂O 0.27(4), BaO 0.18(6), and MnO 0.08(1), plus Li₂O 1.38 from the LA-ICP-MS measurement and H₂O 3.22 (added to bring the analytical total close to 100%), yielding a total of 99.79% and an empirical chemical formula (K_0.99Ba_0.01)_Σ=1.00(Li _1.04Cu_0.93Na_0.10)_Σ=2.07 (Cu_5.57Mg_0.43Mn_0.01) _Σ=6.01(Si_4.00O₁₁)₂(OH) ₄. Lavinskyite is isotypic with plancheite, Cu₈(Si ₄O₁₁)₂(OH)₄·H₂O, an amphibole derivative. It is orthorhombic, with space group P_cnband unit-cell parameters α = 19.046(2), β = 20.377(2), γ = 5.2497(6) Å, and V = 2037.4(4) Å³. The key difference between lavinskyite and plancheite lies in the coupled substitution of K ⁺ and Li⁺ in the former for H₂O and Cu ²⁺ in the latter, respectively. The structure of lavinskyite is characterized by the undulating, brucite-like layers consisting of three distinct octahedral sites occupied mainly by Cu. These layers are sandwiched by the amphibole-type double silicate chains extending along the c axis, forming a sheet structure of compact silicate-Cu-silicate triple layers. Adjacent sheets are linked together by K and M4 (= Cu + Li) cations, as well as hydrogen bonding. The M4 site is split, with Cu and Li occupying two different sites. Lavinskyite exhibits more amphibole-like structural features than plancheite, as a consequence of K in the large cavity between the two back-to-back double silicate chains.

Original language	English (US)
Pages (from-to)	525-530
Number of pages	6
Journal	American Mineralogist
Volume	99
Issue number	2-3
DOIs	https://doi.org/10.1515/am.2014.4601
State	Published - Feb 2014

Keywords

K(LiCu)Cu6(Si4O11)2(OH)4
Lavinskyite
Raman spectra
X-ray diffraction
crystal structure
plancheite

ASJC Scopus subject areas

Geophysics
Geochemistry and Petrology

Access to Document

10.1515/am.2014.4601

Cite this

@article{765b5ff81b02413ba45dc49caa01062f,

title = "Lavinskyite, K(LiCu)Cu6(Si4O11) 2(OH)4, isotypic with plancheite, a new mineral from the Wessels mine, Kalahari Manganese Fields, South Africa",

abstract = "A new mineral species, lavinskyite, ideally K(LiCu2+)Cu 62+(Si4O11)2(OH) 4 (IMA 2012-028), has been found in the Wessels mine, Kalahari Manganese Fields, Northern Cape Province, South Africa. Associated minerals include wesselsite, pectolite, richterite, sugilite, and scottyite. Lavinskyite crystals are tabular [parallel to (010)]. The mineral is light blue, transparent with very pale blue streak and vitreous luster. It is brittle and has a Mohs hardness of 5; cleavage is perfect on \{010\} and no parting was observed. The measured and calculated densities are 3.61(3) and 3.62 g/cm3, respectively. Optically, lavinskyite is biaxial (+), with α = 1.675(1), β = 1.686(1), γ = 1.715(1), 2Vmeas = 64(2) . An electron microprobe analysis produced an average composition (wt\%) of SiO2 42.85(10), CuO 46.13(23), K2O 4.16(2), MgO 1.53(17), Na2O 0.27(4), BaO 0.18(6), and MnO 0.08(1), plus Li2O 1.38 from the LA-ICP-MS measurement and H2O 3.22 (added to bring the analytical total close to 100\%), yielding a total of 99.79\% and an empirical chemical formula (K0.99Ba0.01)Σ=1.00(Li 1.04Cu0.93Na0.10)Σ=2.07 (Cu5.57Mg0.43Mn0.01) Σ=6.01(Si4.00O11)2(OH) 4. Lavinskyite is isotypic with plancheite, Cu8(Si 4O11)2(OH)4·H2O, an amphibole derivative. It is orthorhombic, with space group Pcnband unit-cell parameters α = 19.046(2), β = 20.377(2), γ = 5.2497(6) {\AA}, and V = 2037.4(4) {\AA}3. The key difference between lavinskyite and plancheite lies in the coupled substitution of K + and Li+ in the former for H2O and Cu 2+ in the latter, respectively. The structure of lavinskyite is characterized by the undulating, brucite-like layers consisting of three distinct octahedral sites occupied mainly by Cu. These layers are sandwiched by the amphibole-type double silicate chains extending along the c axis, forming a sheet structure of compact silicate-Cu-silicate triple layers. Adjacent sheets are linked together by K and M4 (= Cu + Li) cations, as well as hydrogen bonding. The M4 site is split, with Cu and Li occupying two different sites. Lavinskyite exhibits more amphibole-like structural features than plancheite, as a consequence of K in the large cavity between the two back-to-back double silicate chains.",

keywords = "K(LiCu)Cu6(Si4O11)2(OH)4, Lavinskyite, Raman spectra, X-ray diffraction, crystal structure, plancheite",

author = "Hexiong Yang and Downs, \{Robert T.\} and Evans, \{Stanley H.\} and Pinch, \{William W.\}",

note = "Funding Information: This study was funded by the Science Foundation Arizona.",

year = "2014",

month = feb,

doi = "10.1515/am.2014.4601",

language = "English (US)",

volume = "99",

pages = "525--530",

journal = "American Mineralogist",

issn = "0003-004X",

publisher = "Walter de Gruyter GmbH",

number = "2-3",

}

TY - JOUR

T1 - Lavinskyite, K(LiCu)Cu6(Si4O11) 2(OH)4, isotypic with plancheite, a new mineral from the Wessels mine, Kalahari Manganese Fields, South Africa

AU - Yang, Hexiong

AU - Downs, Robert T.

AU - Evans, Stanley H.

AU - Pinch, William W.

N1 - Funding Information: This study was funded by the Science Foundation Arizona.

PY - 2014/2

Y1 - 2014/2

N2 - A new mineral species, lavinskyite, ideally K(LiCu2+)Cu 62+(Si4O11)2(OH) 4 (IMA 2012-028), has been found in the Wessels mine, Kalahari Manganese Fields, Northern Cape Province, South Africa. Associated minerals include wesselsite, pectolite, richterite, sugilite, and scottyite. Lavinskyite crystals are tabular [parallel to (010)]. The mineral is light blue, transparent with very pale blue streak and vitreous luster. It is brittle and has a Mohs hardness of 5; cleavage is perfect on {010} and no parting was observed. The measured and calculated densities are 3.61(3) and 3.62 g/cm3, respectively. Optically, lavinskyite is biaxial (+), with α = 1.675(1), β = 1.686(1), γ = 1.715(1), 2Vmeas = 64(2) . An electron microprobe analysis produced an average composition (wt%) of SiO2 42.85(10), CuO 46.13(23), K2O 4.16(2), MgO 1.53(17), Na2O 0.27(4), BaO 0.18(6), and MnO 0.08(1), plus Li2O 1.38 from the LA-ICP-MS measurement and H2O 3.22 (added to bring the analytical total close to 100%), yielding a total of 99.79% and an empirical chemical formula (K0.99Ba0.01)Σ=1.00(Li 1.04Cu0.93Na0.10)Σ=2.07 (Cu5.57Mg0.43Mn0.01) Σ=6.01(Si4.00O11)2(OH) 4. Lavinskyite is isotypic with plancheite, Cu8(Si 4O11)2(OH)4·H2O, an amphibole derivative. It is orthorhombic, with space group Pcnband unit-cell parameters α = 19.046(2), β = 20.377(2), γ = 5.2497(6) Å, and V = 2037.4(4) Å3. The key difference between lavinskyite and plancheite lies in the coupled substitution of K + and Li+ in the former for H2O and Cu 2+ in the latter, respectively. The structure of lavinskyite is characterized by the undulating, brucite-like layers consisting of three distinct octahedral sites occupied mainly by Cu. These layers are sandwiched by the amphibole-type double silicate chains extending along the c axis, forming a sheet structure of compact silicate-Cu-silicate triple layers. Adjacent sheets are linked together by K and M4 (= Cu + Li) cations, as well as hydrogen bonding. The M4 site is split, with Cu and Li occupying two different sites. Lavinskyite exhibits more amphibole-like structural features than plancheite, as a consequence of K in the large cavity between the two back-to-back double silicate chains.

AB - A new mineral species, lavinskyite, ideally K(LiCu2+)Cu 62+(Si4O11)2(OH) 4 (IMA 2012-028), has been found in the Wessels mine, Kalahari Manganese Fields, Northern Cape Province, South Africa. Associated minerals include wesselsite, pectolite, richterite, sugilite, and scottyite. Lavinskyite crystals are tabular [parallel to (010)]. The mineral is light blue, transparent with very pale blue streak and vitreous luster. It is brittle and has a Mohs hardness of 5; cleavage is perfect on {010} and no parting was observed. The measured and calculated densities are 3.61(3) and 3.62 g/cm3, respectively. Optically, lavinskyite is biaxial (+), with α = 1.675(1), β = 1.686(1), γ = 1.715(1), 2Vmeas = 64(2) . An electron microprobe analysis produced an average composition (wt%) of SiO2 42.85(10), CuO 46.13(23), K2O 4.16(2), MgO 1.53(17), Na2O 0.27(4), BaO 0.18(6), and MnO 0.08(1), plus Li2O 1.38 from the LA-ICP-MS measurement and H2O 3.22 (added to bring the analytical total close to 100%), yielding a total of 99.79% and an empirical chemical formula (K0.99Ba0.01)Σ=1.00(Li 1.04Cu0.93Na0.10)Σ=2.07 (Cu5.57Mg0.43Mn0.01) Σ=6.01(Si4.00O11)2(OH) 4. Lavinskyite is isotypic with plancheite, Cu8(Si 4O11)2(OH)4·H2O, an amphibole derivative. It is orthorhombic, with space group Pcnband unit-cell parameters α = 19.046(2), β = 20.377(2), γ = 5.2497(6) Å, and V = 2037.4(4) Å3. The key difference between lavinskyite and plancheite lies in the coupled substitution of K + and Li+ in the former for H2O and Cu 2+ in the latter, respectively. The structure of lavinskyite is characterized by the undulating, brucite-like layers consisting of three distinct octahedral sites occupied mainly by Cu. These layers are sandwiched by the amphibole-type double silicate chains extending along the c axis, forming a sheet structure of compact silicate-Cu-silicate triple layers. Adjacent sheets are linked together by K and M4 (= Cu + Li) cations, as well as hydrogen bonding. The M4 site is split, with Cu and Li occupying two different sites. Lavinskyite exhibits more amphibole-like structural features than plancheite, as a consequence of K in the large cavity between the two back-to-back double silicate chains.

KW - K(LiCu)Cu6(Si4O11)2(OH)4

KW - Lavinskyite

KW - Raman spectra

KW - X-ray diffraction

KW - crystal structure

KW - plancheite

UR - https://www.scopus.com/pages/publications/84894581275

UR - https://www.scopus.com/pages/publications/84894581275#tab=citedBy

U2 - 10.1515/am.2014.4601

DO - 10.1515/am.2014.4601

M3 - Article

AN - SCOPUS:84894581275

SN - 0003-004X

VL - 99

SP - 525

EP - 530

JO - American Mineralogist

JF - American Mineralogist

IS - 2-3

ER -