Geigerite Mineral Data
General Geigerite Information
Chemical Formula:
Mn5(AsO3OH)2(AsO4)2•10(H2O)
Composition:
Molecular Weight = 1,012.54 gm
Manganese 27.13 % Mn 35.03 % MnO
Arsenic 29.60 % As 45.40 % As2 O5
Hydrogen 2.19 % H 19.57 % H2 O
Oxygen 41.08 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Mn2+ 5 (AsO3 OH)2 (AsO4 )2 •10(H2 O)
Environment:
Cavities in radiolarites, formed by metamorphism of manganese oxide ores.
IMA Status:
Approved IMA 1989
Locality:
Falotta mine, Oberhalbstein, Graub�unden, Switzerland. Link to MinDat.org Location Data.
Name Origin:
Named for Thomas Geiger (1886-1976), Wiesendangen, Switzerland, who studied Falotta manganese ores.
Name Pronunciation:
Geigerite + Pronunciation
Synonym:
ICSD 68637
PDF 45-1347
Geigerite Image
Images:
Geigerite
Comments: Small, brownish grains of transparent geigerite (see lower image) in a silicous breccia.
Location: Mt. Nero Mine, Borghetto di Vara, La Spieza, Italy.
Scale: 3.5 x 1.5 cm.
© Rich Geiger
Geigerite Crystallography
Axial Ratios:
a:b:c =0.743:1:0.6332
Cell Dimensions:
a = 7.944, b = 10.691, c = 6.77, Z = 1; alpha = 80.97°, beta = 84.2°, gamma = 81.85° V = 559.23 Den(Calc)= 3.01
Crystal System:
Triclinic - Pinacoidal H-M Symbol ( 1 ) Space Group: P1
X Ray Diffraction:
By Intensity(I/Io ): 10.45(1), 3.051(0.24), 3.507(0.21),
Physical Properties of Geigerite
Cleavage:
{???} Perfect
Color:
Red, Colorless.
Density:
3.05
Diaphaneity:
Transparent to Translucent
Hardness:
3 - Calcite
Luster:
Vitreous - Pearly
Streak:
white
Optical Properties of Geigerite
Gladstone-Dale:
CI meas = 0.012 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = -0.005 (Superior) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2101,KPDmeas = 0.2067,KC = 0.2091 Ncalc = 1.63 - 1.64
Optical Data:
Biaxial (-), a=1.601, b=1.63, g=1.66, bire=0.0590, 2V(Calc)=88, 2V(Meas)=89.
Calculated Properties of Geigerite
Electron Density:
Bulk Density (Electron Density)=2.89 gm/cc note: Specific Gravity of Geigerite =3.00 gm/cc.
Fermion Index:
Fermion Index = 0.0002004855 Boson Index = 0.9997995145
Photoelectric:
PEGeigerite = 26.95 barns/electronU=PEGeigerite x r Electron Density= 77.78 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Geigerite is Not Radioactive
Geigerite Classification
Dana Class:
39.02.06.02 (39) Hydrated Acid Phosphates, etc
(39.02) H2 (AB)5 (XO4)4 � x(H2O)
(39.02.06) Dana Group
39.02.06.01 Chudobaite (Mg,Zn)5(AsO3OH)2(AsO4)2•10(H2O) P1 1
39.02.06.02 Geigerite Mn5(AsO3OH)2(AsO4)2•10(H2O) P1 1
Strunz Class:
08.CE.05 08 - PHOSPHATES, ARSENATES, VANADATES
08.C - Phosphates without Additional Anions, with H2O
08.CE -With only medium-sized cations, RO4:H2O � 1:2.5
08.CE.05 Chudobaite (Mg,Zn)5(AsO3OH)2(AsO4)2•10(H2O) P1 1
08.CE.05 Geigerite Mn5(AsO3OH)2(AsO4)2•10(H2O) P1 1
Other Geigerite Information
References:
NAME( AntBidBlaNic4) PHYS. PROP.(Am.Min.,Vol.74,p676-684,1989) OPTIC PROP.(Am.Min.,Vol.74,p676-684,1989)
See Also:
Links to other databases for Geigerite :
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
15 - WWW-MINCRYST
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Geigerite
Mn5(AsO3OH)2(AsO4)2•10(H2O)
Dana No: 39.02.06.02 Strunz No: 08.CE.05
Locality:
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