Home Edgrewite Ca9(SiO4)4F2-hydroxyledgrewite Ca9(SiO4)4(OH)2, a new series of calcium humite-group minerals from altered xenoliths in the ignimbrite of Upper Chegem caldera, Northern Caucasus, Kabardino-Balkaria, Russia
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Edgrewite Ca9(SiO4)4F2-hydroxyledgrewite Ca9(SiO4)4(OH)2, a new series of calcium humite-group minerals from altered xenoliths in the ignimbrite of Upper Chegem caldera, Northern Caucasus, Kabardino-Balkaria, Russia

  • Evgeny V. Galuskin EMAIL logo , Biljana Lazic , Thomas Armbruster , Irina O. Galuskina , Nikolai N. Pertsev , Viktor M. Gazeev , Roman Włodyka , Mateusz Dulski , Piotr Dzierżanowski , Aleksandr E. Zadov and Leonid S. Dubrovinsky
Published/Copyright: April 2, 2015
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American Mineralogist
From the journal American Mineralogist Volume 97 Issue 11-12

Abstract

Members of the edgrewite Ca9(SiO4)4F2-hydroxyledgrewite Ca9(SiO4)4(OH)2 series, structural analogues of clinohumite-hydroxylclinohumite series, Mg9(SiO4)4(F,OH)2, were discovered in xenoliths of carbonate-silicate rock altered to skarn within ignimbrites of the Upper Chegem volcanic structure, Kabardino-Balkaria, Northern Caucasus, Russia. The new minerals occur sparingly in zones containing bultfonteinite, hillebrandite, jennite, and chegemite, as well as rare relics of larnite and rondorfite enclosed in a matrix of hydroxylellestadite. Edgrewite and hydroxyledgrewite are largely altered to jennite in places with admixed zeophyllite and trabzonite, and are preserved as elongate relics mostly 0.1-0.4 mm long in the central part of atoll-like pseudomorphs. The new minerals form a solid-solution series Ca9(SiO4)4(F,OH)2, in which the content of the edgrewite end-member Ca9(SiO4)4F2 ranges from 74% (F = 3.64 wt%) to 31% (F = 1.52 wt%).

Structure refinement of crystals containing 51% and 37% of the edgrewite end-member gave, respectively, R1 = 3.03%, space group P21/b11 (no. 14), Z = 2, a = 5.06870(10), b = 11.35790(10), c = 15.4004(2) Å, α = 100.5980(10)°, V = 871.47(3) Å3; and R1 = 1.61%, space group P21/b11 (no. 14), Z = 2, a = 5.06720(10), b = 11.35450(10), c = 15.3941(2) Å, α = 100.5870(10)°, and V = 870.63(2) Å3.

Minerals of the edgrewite-hydroxyledgrewite series are colorless, optically biaxial (+), 2Vmeas = 80(5)°; 2Vcalc = 78.7°; dispersion r > v, medium; orientation: Z = a, X ^ c = 12(2)°; edgrewite: α = 1.621(2), β = 1.625(2), γ = 1.631(2); hydroxyledgrewite: α = 1.625(2), β = 1.629(2), γ = 1.635(2) (589 nm). The micro-hardness VHN50 = 352-366 kg/mm2 corresponds to the Mohs scale of 5.5-6. 5. FTIR spectra of edgrewite and hydroxyledgrewite show resolved bands at (edgrewite/hydroxyledgrewite, cm-1): 3558 and 3551 and 3543/3554, absent/3486, 1075/1075, 996/996, 980/982, 934/933, 917/918, 904/903, 890/884, 864/864, 842/842, 818/820. Raman spectra are characterized by the following bands (edgrewite/hydroxyledgrewite, cm-1) at: 921/923, 889/890, 839/840, and 815/814 (SiO4 stretching), at: 556/559, 527/527, 423/419, 406/404, and 394/394 (SiO4 bending), 309/295, 269/256, and 163/166 (CaO6). In the OH stretching region three bands are noted at 3554, 3547, and 3540 cm-1 for edgrewite and two - 3550 and 3475 cm-1 for hydroxyledgrewite confirming the corresponding IR spectra. The major difference in Raman and IR spectra of edgrewite and hydroxyledgrewite is the presence of two resolved peaks in the OH stretching region at ca. 3550 and 3480 cm-1 for hydroxyledgrewite.

Keywords : New mineral; edgrewite; hydroxyledgrewite; humite; structure; Raman; FTIR; Russia
Received: 2012-3-7
Accepted: 2012-7-26
Published Online: 2015-4-2
Published in Print: 2012-11-1

© 2015 by Walter de Gruyter Berlin/Boston

Articles in the same Issue

  1. Cation ordering over short-range and long-range scales in the MgAl2O4-CuAl2O4 series
  2. Blue spinel crystals in the MgAl2O4-CoAl2O4 series: Part I. Flux growth and chemical characterization
  3. Blue spinel crystals in the MgAl2O4-CoAl2O4 series: Part II. Cation ordering over short-range and long-range scales
  4. CO2 solubility in primitive martian basalts similar to Yamato 980459, the effect of composition on CO2 solubility of basalts, and the evolution of the martian atmosphere
  5. New structural features of the high-pressure synthetic sheet-disilicate Phase-X, K(2–x)Mg2Si2O7Hx
  6. Crystal structure refinements of borate dimorphs inderite and kurnakovite using 11B and 25Mg nuclear magnetic resonance and DFT calculations
  7. Hydrogen-bond system and dehydration behavior of the natural zeolite parthéite
  8. In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study
  9. LREE-redistribution among fluorapatite, monazite, and allanite at high pressures and temperatures
  10. A single-crystal neutron diffraction study of hambergite, Be2BO3(OH,F)
  11. Analyzing water contents in unexposed glass inclusions in quartz crystals
  12. The atomic structure of deuterated boyleite ZnSO4·4D2O, ilesite MnSO4·4D2O, and bianchite ZnSO4·6D2O
  13. Synthesis and crystal chemistry of Fe3+-bearing (Mg,Fe3+)(Si,Fe3+)O3 perovskite
  14. Mixed-layered structure formation during trans-vacant Al-rich illite partial dehydroxylation
  15. Structural regularities in 2M1 dioctahedral micas: The structure modeling approach
  16. Incorporation of Fe and Al in MgSiO3 perovskite: An investigation by 27Al and 29Si NMR spectroscopy
  17. In situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite
  18. Packing systematics and structural relationships of the new copper molybdate markascherite and related minerals
  19. On the origin of sellaite (MgF2)-rich deposits in Mg-poor environments
  20. Edgrewite Ca9(SiO4)4F2-hydroxyledgrewite Ca9(SiO4)4(OH)2, a new series of calcium humite-group minerals from altered xenoliths in the ignimbrite of Upper Chegem caldera, Northern Caucasus, Kabardino-Balkaria, Russia
  21. Whelanite, Cu2Ca6[Si6O17(OH)](CO3)(OH)3(H2O)2, an (old) new mineral from the Bawana mine, Milford, Utah
  22. 2M1-phlogopite from Black Hills (South Australia): The first case of configurational polytype in micas
  23. Oxy-chromium-dravite, NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup
  24. First-principles study of self-diffusion and viscous flow in diopside (CaMgSi2O6) liquid
  25. Browneite, MnS, a new sphalerite-group mineral from the Zakłodzie meteorite
  26. Mineralogical variation of silica induced by Al and Na in hydrothermal solutions
https://doi.org/10.2138/am.2012.4161
Keywords for this article
New mineral; edgrewite; hydroxyledgrewite; humite; structure; Raman; FTIR; Russia

Articles in the same Issue

  1. Cation ordering over short-range and long-range scales in the MgAl2O4-CuAl2O4 series
  2. Blue spinel crystals in the MgAl2O4-CoAl2O4 series: Part I. Flux growth and chemical characterization
  3. Blue spinel crystals in the MgAl2O4-CoAl2O4 series: Part II. Cation ordering over short-range and long-range scales
  4. CO2 solubility in primitive martian basalts similar to Yamato 980459, the effect of composition on CO2 solubility of basalts, and the evolution of the martian atmosphere
  5. New structural features of the high-pressure synthetic sheet-disilicate Phase-X, K(2–x)Mg2Si2O7Hx
  6. Crystal structure refinements of borate dimorphs inderite and kurnakovite using 11B and 25Mg nuclear magnetic resonance and DFT calculations
  7. Hydrogen-bond system and dehydration behavior of the natural zeolite parthéite
  8. In situ dehydration behavior of zeolite-like cavansite: A single-crystal X-ray study
  9. LREE-redistribution among fluorapatite, monazite, and allanite at high pressures and temperatures
  10. A single-crystal neutron diffraction study of hambergite, Be2BO3(OH,F)
  11. Analyzing water contents in unexposed glass inclusions in quartz crystals
  12. The atomic structure of deuterated boyleite ZnSO4·4D2O, ilesite MnSO4·4D2O, and bianchite ZnSO4·6D2O
  13. Synthesis and crystal chemistry of Fe3+-bearing (Mg,Fe3+)(Si,Fe3+)O3 perovskite
  14. Mixed-layered structure formation during trans-vacant Al-rich illite partial dehydroxylation
  15. Structural regularities in 2M1 dioctahedral micas: The structure modeling approach
  16. Incorporation of Fe and Al in MgSiO3 perovskite: An investigation by 27Al and 29Si NMR spectroscopy
  17. In situ high-temperature Raman and FTIR spectroscopy of the phase transformation of lizardite
  18. Packing systematics and structural relationships of the new copper molybdate markascherite and related minerals
  19. On the origin of sellaite (MgF2)-rich deposits in Mg-poor environments
  20. Edgrewite Ca9(SiO4)4F2-hydroxyledgrewite Ca9(SiO4)4(OH)2, a new series of calcium humite-group minerals from altered xenoliths in the ignimbrite of Upper Chegem caldera, Northern Caucasus, Kabardino-Balkaria, Russia
  21. Whelanite, Cu2Ca6[Si6O17(OH)](CO3)(OH)3(H2O)2, an (old) new mineral from the Bawana mine, Milford, Utah
  22. 2M1-phlogopite from Black Hills (South Australia): The first case of configurational polytype in micas
  23. Oxy-chromium-dravite, NaCr3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup
  24. First-principles study of self-diffusion and viscous flow in diopside (CaMgSi2O6) liquid
  25. Browneite, MnS, a new sphalerite-group mineral from the Zakłodzie meteorite
  26. Mineralogical variation of silica induced by Al and Na in hydrothermal solutions
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