Geigerite
A valid IMA mineral species
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About Geigerite
Thomas Geiger (1920 - 1990)
Formula:
Mn2+5(AsO4)2(HAsO4)2 · 10H2O
Colour:
Very faint rose-red color. Isolated crystals appear almost colorless.
Lustre:
Vitreous, Pearly
Hardness:
3
Specific Gravity:
3.05
Crystal System:
Triclinic
Member of:
Name:
Named after Dr. Thomas Geiger (1920 - 1990), Swiss mineralogist and metallurgist in the machinery industry and specialist for the manganese ores and minerals of Falotta and Alp Parsettens to which he devoted his PhD thesis and a series of later studies.
Unique Identifiers
Mindat ID:
1669
Long-form identifier:
mindat:1:1:1669:4
Similar Names
| Geierite | A synonym of 'Geyerite' |
IMA Classification of Geigerite
Approved
IMA Formula:
Mn2+5(As5+O4)2(As5+O3OH)2·10H2O
Approval year:
1985
First published:
1989
Classification of Geigerite
8.CE.05
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
39.2.6.2
39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
2 : (AB)5[HXO4]2[XO4]2.xH2O
39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
2 : (AB)5[HXO4]2[XO4]2.xH2O
20.8.10
20 : Arsenates (also arsenates with phosphate, but without other anions)
8 : Arsenates of Mn
20 : Arsenates (also arsenates with phosphate, but without other anions)
8 : Arsenates of Mn
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ggr | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Geigerite
Vitreous, Pearly
Transparency:
Transparent
Colour:
Very faint rose-red color. Isolated crystals appear almost colorless.
Streak:
White
Hardness:
3 on Mohs scale
Hardness:
VHN20=105 kg/mm2 - Vickers
Comment:
VHN,50g = 115 kg/mm3
Tenacity:
Very brittle
Cleavage:
Perfect
Parallel to {010}
Parallel to {010}
Density:
3.05(10) g/cm3 (Measured) 3.00 g/cm3 (Calculated)
Comment:
Measured using heavy liquids
Optical Data of Geigerite
Type:
Biaxial (-)
RI values:
nα = 1.601 nβ = 1.630 nγ = 1.660
2V:
Measured: 89° , Calculated: 88°
Max. Birefringence:
δ = 0.059
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
none
Optical Extinction:
Z > Y ~ X.
Pleochroism:
Weak
Comments:
Very weakly visible in thicker crystals, colorless to rose-red.
Comments:
X ~ b, Y ~ a, Z ~ c. On {010}: Z Λ c~ 15°, on {100}: Z Λ c~ 6°, X almost normal to {010}.
Chemistry of Geigerite
Mindat Formula:
Mn2+5(AsO4)2(HAsO4)2 · 10H2O
Element Weights:
Elements listed:
Crystallography of Geigerite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 7.94 Å, b = 10.69 Å, c = 6.77 Å
α = 80.97°, β = 84.2°, γ = 81.85°
α = 80.97°, β = 84.2°, γ = 81.85°
Ratio:
a:b:c = 0.743 : 1 : 0.633
Unit Cell V:
560.3 ų
Z:
1
Morphology:
Platy on {010}, with striation parallel to the c axis
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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CIF File Best | x | y | z | a | b | c
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Labels
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0001248 | Geigerite | Graeser S, Schwander H, Bianchi R, Pilati T, Gramaccioli C M (1989) Geigerite, the Mn analogue of chudobaite: Its description and crystal structure American Mineralogist 74 676-684 |  | 1989 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.45 Å | (100) |
| 7.85 Å | (13) |
| 3.507 Å | (21) |
| 3.340 Å | (20) |
| 3.051 Å | (24) |
| 3.011 Å | (17) |
| 2.786 Å | (14) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47e : [Vanadates, chromates, manganates] |
Type Occurrence of Geigerite
General Appearance of Type Material:
Covers the rock in minute crystals, rarely exceeding 0.5 mm in length, on areas of the order of 1 cm2. Also, massive, fine-grained to fibrous aggregates up to 1 cm in length.
Place of Conservation of Type Material:
Natural History Museum, Basel, and at the Mineralogical Institute, University of Basel.
Geological Setting of Type Material:
Alpine metamorphism of manganese ores, with abundant As in surrounding rock
Synonyms of Geigerite
Other Language Names for Geigerite
Relationship of Geigerite to other Species
Member of:
Other Members of Ondrušite Group:
| Chudobaite | Mg5(AsO4)2(AsO3OH)2 · 10H2O | Tric. 1 : P1 |
| Klajite | MnCu4(AsO4)2(HAsO4)2 · 9-10H2O | Tric. 1 : P1 |
| Ondrušite | CaCu4(AsO4)2(HAsO4)2 · 10H2O | Tric. 1 : P1 |
Common Associates
Associations Based on Photo Data:
| 2 photos of Geigerite associated with Villyaellenite | (Mn,Ca)Mn2Ca2(AsO3OH)2(AsO4)2 · 4H2O |
| 1 photo of Geigerite associated with Sarkinite | Mn2+2(AsO4)(OH) |
| 1 photo of Geigerite associated with Calcite | CaCO3 |
| 1 photo of Geigerite associated with 'Manganese Oxides' |
Related Minerals - Strunz-mindat Grouping
| 8.CE. | Monteneroite | Cu2+Mn2+2(AsO4)2 · 8H2O |
| 8.CE. | Belmonteite | CaMn2(AsO4)2 · 7H2O |
| 8.CE. | Zincocabrerite | ZnMg2(AsO4)2(H2O)8 |
| 8.CE.X | Babánekite | Cu3(AsO4)2 · 8H2O |
| 8.CE.05 | Chudobaite | Mg5(AsO4)2(AsO3OH)2 · 10H2O |
| 8.CE.10 | Newberyite | Mg(PO3OH) · 3H2O |
| 8.CE.10 | Manganonewberyite | Mn(PO3OH)(H2O)3 |
| 8.CE.15 | Fanguangite | (MoO2)(PO3OH) · 4H2O |
| 8.CE.15 | Brassite | Mg(HAsO4) · 4H2O |
| 8.CE.20 | Phosphorrösslerite | Mg(PO3OH) · 7H2O |
| 8.CE.20 | Rösslerite | Mg(HAsO4) · 7H2O |
| 8.CE.25 | Switzerite | Mn2+3(PO4)2 · 7H2O |
| 8.CE.25 | Metaswitzerite | Mn2+3(PO4)2 · 4H2O |
| 8.CE.30 | Pradetite | CoCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Veselovskýite | ZnCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Lindackerite | CuCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Klajite | MnCu4(AsO4)2(HAsO4)2 · 9-10H2O |
| 8.CE.30 | Hloušekite | (Ni,Co)Cu4(AsO4)2(AsO3OH)2 · 9H2O |
| 8.CE.30 | Ondrušite | CaCu4(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.35 | Bobierrite | Mg3(PO4)2 · 8H2O |
| 8.CE.40 | Barićite | (Mg,Fe)3(PO4)2 · 8H2O |
| 8.CE.40 | Parasymplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Gritsenkoite | CoMg2(AsO4)2(H2O)8 |
| 8.CE.40 | Cabrerite | NiMg2(AsO4)2 · 8H2O |
| 8.CE.40 | Pakhomovskyite | Co3(PO4)2 · 8H2O |
| 8.CE.40 | Vivianite | Fe2+Fe2+2(PO4)2 · 8H2O |
| 8.CE.40 | Arupite | Ni3(PO4)2 · 8H2O |
| 8.CE.40 | Erythrite | Co3(AsO4)2 · 8H2O |
| 8.CE.40 | Hörnesite | Mg3(AsO4)2 · 8H2O |
| 8.CE.40 | Manganohörnesite | Mn2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Köttigite | Zn3(AsO4)2 · 8H2O |
| 8.CE.40 | Ferrisymplesite | Fe3+3(AsO4)2(OH)3 · 5H2O |
| 8.CE.40 | Annabergite | Ni3(AsO4)2 · 8H2O |
| 8.CE.45 | Symplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.50 | Cattiite | Mg3(PO4)2 · 22H2O |
| 8.CE.55 | Koninckite | Fe3+PO4 · 3H2O |
| 8.CE.60 | Kaňkite | FeAsO4 · 3.5H2O |
| 8.CE.60 | Hilarionite | Fe3+2(SO4)(AsO4)(OH) · 6H2O |
| 8.CE.65 | Steigerite | Al(VO4) · 3H2O |
| 8.CE.70 | Metaschoderite | Al2(PO4)(VO4) · 6H2O |
| 8.CE.70 | Schoderite | Al2(PO4)(VO4) · 8H2O |
| 8.CE.75 | Zigrasite | MgZr(PO4)2 · 4H2O |
| 8.CE.75 | 'UM2009-11-PO:CaHZr' | CaZr[PO4]2 · 4H2O |
| 8.CE.75 | Malhmoodite | FeZr(PO4)2 · 4H2O |
| 8.CE.80 | Santabarbaraite | Fe3+3(PO4)2(OH)3 · 5H2O |
| 8.CE.85 | Metaköttigite | (Zn,Fe,Fe)3(AsO4)2 · 8(H2O,OH) |
| 8.CE.90 | Slavkovite | Cu13(AsO4)6(AsO3OH)4 · 23H2O |
Fluorescence of Geigerite
None
Other Information
IR Spectrum:
cm-1, transmittance in percent:
3428 (27.6), 1643 (74.5), 824 (27.6),714 (61.1), 400 (48.3), and 370 (47.3).
3428 (27.6), 1643 (74.5), 824 (27.6),714 (61.1), 400 (48.3), and 370 (47.3).
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Geigerite
mindat.org URL:
https://www.mindat.org/min-1669.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Geigerite
Localities for Geigerite
Showing 8 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
China | |
| |
Italy | |
| Cabella et al. (2000) |
Japan | |
| Kato et al (1990) +1 other reference |
| 島倉広至 et al. (2015) |
Romania | |
| Collected by Gábor Koller |
Saudi Arabia | |
| Faheha et al. (2012) |
Switzerland (TL) | |
| Graeser et al. (1989) +1 other reference |
| Raman & EDX through AMI identificaton ... +1 other reference |
Quick NavTopAbout GeigeriteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Săcărâmb, Certeju de Sus, Hunedoara County, Romania