Voltaite Mineral Data

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 % K₂O

Aluminum 1.33 % Al 2.51 % Al₂O₃

Iron 22.02 % Fe 17.70 % FeO / 11.81 % Fe₂O₃

Hydrogen 1.79 % H 15.98 % H₂O

Sulfur 18.96 % S 47.35 % SO₃

Oxygen 52.04 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K₂Fe²⁺₅Fe³⁺₃Al(SO₄)₁₂·18(H₂O)

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).

Synonym:

ICSD 9254

Monsmedite

PDF 20-1388

Voltaite Image

Images:

Voltaite Alunogen

Comments: Dark greenish-black crystals of voltaite on white alunogen.
Location: Carola Mine, Freital, Dresden, Saxony, Germany. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Voltaite Szomolnokite

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 - HexoctahedralH-M Symbol (4/m 3 2/m) Space Group: F d3c

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.54(1), 3.41(0.9), 5.57(0.7),

Crystal Structure:

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Mereiter K , Tschermaks Mineralogische und Petrographische Mitteilungen , 18 (1972) p.185-202, Die kristallstruktur des voltaits, K2Fe2+5Fe3+3Al[SO4]12*18H2O

Physical Properties of Voltaite

Cleavage:

None

Color:

Greenish black, Dark green, Olive green, Black.

Density:

2.6 - 2.8, Average = 2.7

Diaphaniety:

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:

None.

Luster:

Silky

Streak:

grayish green

Optical Properties of Voltaite

Optical Data:

Isotropic, n=1.593-1.608.

Calculated Properties of Voltaite

Electron Density:

r_electron=2.69 gm/cc
note: r_Voltaite=2.69 gm/cc.

Fermion Index

Fermion Index = 0.00634
Boson Index = 0.99366

Photoelectric:

PE_Voltaite= 8.02 barns/electron
U=PE_Voltaite x r_electron= 21.59 barns/cc.

Radioactivity:

GRapi = 55.65 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Voltaite - barely detectable

Voltaite Classification

Dana Class:

29.9.1.1 (29)Hydrated Acid and Sulfates

(29.9)with miscellaneous formulae

(29.9.1)Dana Group

29.9.1.1 Voltaite K2Fe5Fe3Al(SO4)12·18(H2O) F d3c 4/m 3 2/m

29.9.1.2 Zincovoltaite K2Zn5Fe3Al(SO4)12·18(H2O) F d3c 4/m 3 2/m

Strunz Class:

VI/C.14-50 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/C - Water-bearing sulfates without unfamiliar anions. cations of medium and very big size

VI/C.14 - Sodium alum - Zincovoltaite series

VI/C.14-10 Sodium-alum NaAl(SO4)2·12(H2O) P a3 2/m 3

VI/C.14-20 Potassium-alum KAl(SO4)2·12(H2O) P a3 2/m 3

VI/C.14-30 Tschermigite (NH4)Al(SO4)2·12(H2O) P a3 2/m 3

VI/C.14-40 Lonecreekite (NH4)(Fe,Al)(SO4)2·12(H2O) P a3 2/m 3

VI/C.14-45 Lanmuchangite! TlAl(SO4)2·12(H2O) P a3 2/m 3

VI/C.14-50 Voltaite K2Fe5Fe3Al(SO4)12·18(H2O) F d3c 4/m 3 2/m

VI/C.14-60 Zincovoltaite K2Zn5Fe3Al(SO4)12·18(H2O) F d3c 4/m 3 2/m

Other Voltaite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Dana8)

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Print or Cut-and-Paste your Voltaite Specimen Label here :

Voltaite

K2Fe++5Fe+++3Al(SO4)12·18(H2O)
Dana No: 29.9.1.1 Strunz No: VI/C.14-50
Locality:

Notes: