Alpersite (Mg,Cu)SO4·7H2O, a new mineral of the melanterite group, and cuprian pentahydrite: Their occurrence within mine waste
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Ronald C. Peterson
,
Jane M. Hammarstrom
Abstract
Alpersite, Mg0.58Cu0.37Zn0.02Mn0.02Fe0.01SO4·7H2O, a new mineral species with direct relevance to reactions in mine waste, occurs in a mineralogically zoned assemblage in sheltered areas at the abandoned Big Mike mine in central Nevada at a relative humidity of 65% and T = 4 °C. Blue alpersite, which is isostructural with melanterite (FeSO4·7H2O), is overlain by a light blue to white layer dominated by pickeringite, alunogen, and epsomite. X-ray diffraction data (MoKα radiation) from a single crystal of alpersite were refined in P21/c, resulting in wR = 0.05 and cell dimensions α = 14.166(4), b = 6.534(2), c = 10.838(3) Å, β = 105.922(6)°, Z = 4. Site-occupancy refinement, constrained to be consistent with the compositional data, showed Mg to occupy the M1 site and Cu the M2 site. The octahedral distortion of M2 is consistent with 72% Cu occupancy when compared with the site-distortion data of substituted melanterite.
Cuprian pentahydrite, with the formula (Mg0.49Cu0.41Mn0.08Zn0.02)SO4·5H2O, was collected from an efflorescent rim on a depression that had held water in a large waste-rock area near Miami, Arizona. After dissolution of the efflorescence in de-ionized water, and evaporation of the supernatant liquid, alpersite precipitated and quickly dehydrated to cuprian pentahydrite. These observations are consistent with previous experimental studies of the system MgSO4-CuSO4-H2O. It is suspected that alpersite and cuprian pentahydrite are widespread in mine wastes that contain Cu-bearing sulfides, but in which solubilized Fe2+ is not available for melanterite crystallization because of oxidation to Fe3+ in surface waters of near-neutral pH. Alpersite has likely been overlooked in the past because of the close similarity of its physical properties to those of melanterite and chalcanthite. Alpersite is named after Charles N. Alpers, geochemist with the United States Geological Survey, who has made significant contributions to our understanding of the mineralogical controls of mine-water geochemistry.
© 2015 by Walter de Gruyter Berlin/Boston
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Articles in the same Issue
- Presidential Address: Elastic properties of minerals and the influence of phase transitions
- Pressure-induced hydration in zeolite tetranatrolite
- Annealing experiments on induced fission tracks in apatite: Measurements of horizontal-confined track lengths and track densities in basal sections and randomly oriented grains
- Alpersite (Mg,Cu)SO4·7H2O, a new mineral of the melanterite group, and cuprian pentahydrite: Their occurrence within mine waste
- Application of a new vanadium valence oxybarometer to basaltic glasses from the Earth, Moon, and Mars
- Quantitative polarized infrared analysis of trace OH in populations of randomly oriented mineral grains
- Hydrogen incorporation in olivine from 2–12 GPa
- A numerical model for steady-state temperature distributions in solid-medium high-pressure cell assemblies
- Thermodynamics and kinetics of cation ordering in natural and synthetic Mg(Al,Fe3+)2O4 spinels from in situ high-temperature X-ray diffraction
- Kinetics of cation ordering in natural Mg(Al,Cr3+)2O4 spinels
- Equations of state and structures of andalusite to 9.8 GPa and sillimanite to 8.5 GPa
- Equation of state and phase transition in KAlSi3O8 hollandite at high pressure
- A novel arrangement of silicate tetrahedra in the uranyl silicate sheet of oursinite, (Co0.8Mg0.2)[(UO2)(SiO3OH)]2(H2O)6
- Aluminum substitution in stishovite and MgSiO3 perovskite: High-resolution 27Al NMR
- The effect of chlorine on the viscosity of Na2O-Fe2O3-Al2O3-SiO2 melts
- TEM imaging and analysis of microinclusions in diamonds: A close look at diamond-growing fluids
- A partial molar volume for ZnO in silicate melts
- Garnet-spinel intergrowths in ultrahigh-temperature granulite, Eastern Ghats, India: Possible evidence of an early Tschermak-rich orthopyroxene during prograde metamorphism
- The partial molar volume of Fe2O3 in alkali silicate melts: Evidence for an average Fe3+ coordination number near five
- The crystal structure of a second antigorite polysome (m = 16), by single-crystal synchrotron diffraction
- Oxide melt solution calorimetry of sulfides: Enthalpy of formation of sphalerite, galena, greenockite, and hawleyite
- An experimental determination of the effect of pressure on the Fe3+/ΣFe ratio of an anhydrous silicate melt to 3.0 GPa
- Evolution of product phase assemblages during thermal decomposition of muscovite under strong disequilibrium conditions
- Synthetic P21/m amphiboles in the system Li2O-Na2O-MgO-SiO2-H2O (LNMSH)
- Incongruent dissolution of wollastonite measured with vertical scanning interferometry
- Experiments on CaCO3-MgCO3 solid solutions at high pressure and temperature
- Calorimetric data for naturally occurring magnesiocarpholite and ferrocarpholite
- Clinopyroxene exsolution in wollastonite from Namaqualand granulite, South Africa
- Icosahedral coordination of phosphorus in the crystal structure of melliniite, a new phosphide mineral from the Northwest Africa 1054 acapulcoite
- Mechanism for the dissolution of olivine series minerals in acidic solutions
- High-pressure behavior of synthetic antigorite in the MgO-SiO2-H2O system from Raman spectroscopy
- Sinoite (Si2N2O) shocked at pressures of 28 to 64 GPa
- Laser Raman spectroscopic measurements of water in unexposed glass inclusions
- The Mars/Earth dichotomy in Mg/Si and Al/Si ratios: Is it real?
- Equation of state of CaIrO3-type MgSiO3 up to 144 GPa
- Synchrotron infrared spectroscopy of synthetic Na(NaMg)Mg5Si8O22(OH)2 up to 30 GPa: Insight on a new high-pressure amphibole polymorph
