Voltaite Mineral Data
General Voltaite Information
Chemical Formula:
K2Fe++5Fe+++3Al(SO4)12•18(H2O)
Composition:
Molecular Weight = 2,028.99 gm
Potassium 3.85 % K 4.64 % K2 O
Aluminum 1.33 % Al 2.51 % Al2 O3
Iron 22.02 % Fe 17.70 % FeO / 11.81 % Fe2 O3
Hydrogen 1.79 % H 15.98 % H2 O
Sulfur 18.96 % S 47.35 % SO3
Oxygen 52.04 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
K2 Fe2+ 5 Fe3+ 3 Al(SO4 )12 •18(H2 O)
Environment:
Solfatara and fumaroles associated with volcanic activity and continental evaporite deposits.
IMA Status:
Valid Species (Pre-IMA) 1841
Locality:
Pozzuoli near Naples, Italy. Link to MinDat.org Location Data.
Name Origin:
Named after the Italian physicist, Alessandro G. A. A. Volta (1745-1841).
Name Pronunciation:
Voltaite
Synonym:
ICSD 9254
Monsmedite
PDF 20-1388
Voltaite Image
Images:
Images:
Szomolnokite Voltaite
Comments: Whitish crystalline crust of voltaite on crystals of brown szomolnokite.
Location: Alcaparrosa Mine, Cerritos Bayos, Chile.
Scale: Picture size 1 cm.
© John Veevaert
Voltaite Crystallography
Cell Dimensions:
a = 27.178, Z = 16; V = 20,074.86 Den(Calc)= 2.69
Crystal System:
Isometric - Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3c
X Ray Diffraction:
By Intensity(I/Io ): 3.54(1), 3.41(0.9), 5.57(0.7),
Physical Properties of Voltaite
Cleavage:
None
Color:
Greenish black, Dark green, Olive green, Black.
Density:
2.6 - 2.8, Average = 2.7
Diaphaneity:
Opaque
Fracture:
Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Habit:
Crystalline - Fine - Occurs as well-formed fine sized crystals.
Habit:
Massive - Granular - Common texture observed in granite and other igneous rock.
Hardness:
3-3.5 - Calcite-Copper Penny
Luminescence:
Non-fluorescent.
Luster:
Silky
Streak:
grayish green
Optical Properties of Voltaite
Gladstone-Dale:
CI meas = 0.002 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = -0.001 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2232,KPDmeas = 0.2224,KC = 0.2229 Ncalc = 1.58 - 1.62
Optical Data:
Isotropic, n=1.593-1.608.
Calculated Properties of Voltaite
Electron Density:
Bulk Density (Electron Density)=2.69 gm/cc note: Specific Gravity of Voltaite =2.69 gm/cc.
Fermion Index:
Fermion Index = 0.006347623 Boson Index = 0.993652377
Photoelectric:
PEVoltaite = 8.02 barns/electronU=PEVoltaite x r electron = 21.59 barns/cc.
Radioactivity:
GRapi = 55.65 (Gamma Ray American Petroleum Institute Units)
Concentration of Voltaite per GRapi unit = 1.80 (%)
Estimated Radioactivity from Voltaite - barely detectable
Voltaite Classification
Dana Class:
29.09.01.01 (29) Hydrated Acid and Sulfates
(29.09) with miscellaneous formulae
(29.09.01) Voltaite Group
29.09.01.01 Voltaite K2Fe5Fe3Al(SO4)12•18(H2O) F d3c 4/m 3 2/m
29.09.01.02 Zincovoltaite K2Zn5Fe3Al(SO4)12•18(H2O) F d3c 4/m 3 2/m
29.09.01.03 Pertlikite ! K2(Fe,Mg)2(Mg,Fe)4Fe2Al(SO4)12•18H2O I 41 /acd 4/m 2/m 2/m
Strunz Class:
07.CC.25 07 - SULFATES (SELENATES, TELLURATES)
07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O
07.CC -With medium-sized and large cations
07.CC.25 Monsmedite ? H8K2Tl2(SO4)8•11(H2O) F d3c 4/m 3 2/m
07.CC.25 Voltaite K2Fe5Fe3Al(SO4)12•18(H2O) F d3c 4/m 3 2/m
07.CC.25 Zincovoltaite K2Zn5Fe3Al(SO4)12•18(H2O) F d3c 4/m 3 2/m
07.CC.25 Pertlikite ! K2(Fe,Mg)2(Mg,Fe)4Fe2Al(SO4)12•18H2O I 41 /acd 4/m 2/m 2/m
Other Voltaite Information
References:
NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)
See Also:
Links to other databases for Voltaite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
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Voltaite
K2Fe++5Fe+++3Al(SO4)12•18(H2O)
Dana No: 29.09.01.01 Strunz No: 07.CC.25
Locality:
Notes:
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