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 % As₂O₅

Hydrogen 2.19 % H 19.57 % H₂O

Oxygen 41.08 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mn²⁺₅(AsO₃OH)₂(AsO₄)₂•10(H₂O)

Environment:

Cavities in radiolarites, formed by metamorphism of manganese oxide ores.

IMA Status:

Approved IMA 1989

Locality:

Falotta mine, Oberhalbstein, Graubï¿½unden, 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

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

By Intensity(I/I_o): 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:

PE_Geigerite= 26.95 barns/electron
U=PE_Geigerite x rElectron 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 ï¿½ 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 ï¿½ 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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Print or Cut-and-Paste your Geigerite Specimen Label here :

Geigerite

Mn5(AsO3OH)2(AsO4)2•10(H2O)
Dana No: 39.02.06.02 Strunz No: 08.CE.05
Locality:

Notes:

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