Mcgovernite
A valid IMA mineral species - grandfathered
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About Mcgovernite
Formula:
Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21
Colour:
Bronzy-brown, deep red-brown
Lustre:
Pearly
Hardness:
3
Specific Gravity:
3.719
Crystal System:
Trigonal
Member of:
Name:
Named in 1927 by Charles Palache and Lawson Henry Bauer in honor of James J. McGovern [June 1861 Ireland - 1915 Franklin, New Jersey, USA], a mineral collector, and probably mineral dealer, who worked on the picking table for the New Jersey Zinc Company.
The mineral species with the largest number of atoms in the unit cell.
Closely related to carlfrancisite and turtmannite.
Closely related to carlfrancisite and turtmannite.
Unique Identifiers
Mindat ID:
2614
Long-form identifier:
mindat:1:1:2614:3
IMA Classification of Mcgovernite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Zn2+3(Mn2+,Mg,Fe3+,Al)42(As3+O3)2(As5+O4)4[(Si,As5+)O4]8(OH)42
First published:
1927
Classification of Mcgovernite
8.BE.45
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
43.4.9.1
43 : COMPOUND PHOSPHATES, ETC.
4 : Anhydrous Compound Phosphates, etc·, Containing Hydroxyl or Halogen
43 : COMPOUND PHOSPHATES, ETC.
4 : Anhydrous Compound Phosphates, etc·, Containing Hydroxyl or Halogen
17.7.10
17 : Silicates Containing other Anions
7 : Silicates with vanadate, arsenate or antimonate
17 : Silicates Containing other Anions
7 : Silicates with vanadate, arsenate or antimonate
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 |
|---|---|---|
| Mgv | 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 Mcgovernite
Pearly
Transparency:
Translucent
Colour:
Bronzy-brown, deep red-brown
Hardness:
3 on Mohs scale
Cleavage:
Perfect
Micaceous on {0001}
Micaceous on {0001}
Density:
3.719 g/cm3 (Measured) 3.71 g/cm3 (Calculated)
Optical Data of Mcgovernite
Type:
Uniaxial (+)
RI values:
nω = 1.757 nε = 1.76
Max. Birefringence:
δ = 0.003
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:
Very 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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Chemistry of Mcgovernite
Mindat Formula:
Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21
Element Weights:
Common Impurities:
Fe,H20
Crystallography of Mcgovernite
Crystal System:
Trigonal
Class (H-M):
3m - Ditrigonal Pyramidal
Space Group:
R3c
Cell Parameters:
a = 8.190254(12) Å, c = 203.6215(2) Å
Ratio:
a:c = 1 : 24.861
Unit Cell V:
11829 ų
Z:
6
Morphology:
Aggregates of micaceous plates and radial aggregates of platy crystals.
Comment:
Unit cell from Lake and Von Dreele (2025); a = 8.22, c = 203.15 Å were given by Hawthorne (2018). Space group R3c or R3c. (Hawthorne, 2018); Lake and Von Dreele (2025) conclude it is R3c (non-centrosymmetric).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.257 Å | (100) |
| 2.418 Å | (80) |
| 5.630 Å | (70) |
| 2.604 Å | (50) |
| 4.228 Å | (40) |
| 11.205 Å | (30) |
| 2.819 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Mcgovernite
General Appearance of Type Material:
Uniformly granular mass of coarse grain, the individual grains showing an almost micaceous cleavage.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 113888.
Geological Setting of Type Material:
Filling veinlets traversing lean franklinite-zincite ore rich in calcite.
Associated Minerals at Type Locality:
Synonyms of Mcgovernite
Other Language Names for Mcgovernite
Relationship of Mcgovernite to other Species
Member of:
Other Members of Hematolite Group:
| Arakiite | (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23 | Mon. m : Bb |
| Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 | Trig. 3 : R3 |
| Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 | Trig. 3 : R3 |
| Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 | Orth. 222 : C2221 |
| Synadelphite | Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O | Orth. mmm(2/m2/m2/m) : Pnma |
| Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x | Trig. |
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 8.BE.05 | Augelite | Al2(PO4)(OH)3 |
| 8.BE.10 | Grattarolaite | Fe3+3(PO4)O3 |
| 8.BE.15 | Cornetite | Cu3(PO4)(OH)3 |
| 8.BE.20 | Clinoclase | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Gilmarite | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Arhbarite | Cu2Mg(AsO4)(OH)3 |
| 8.BE.30 | Flinkite | Mn2+2Mn3+(AsO4)(OH)4 |
| 8.BE.30 | Argandite | Mn7(VO4)2(OH)8 |
| 8.BE.30 | Raadeite | Mg7(PO4)2(OH)8 |
| 8.BE.30 | Allactite | Mn2+7(AsO4)2(OH)8 |
| 8.BE.35 | 'Mineral E (of Dunn, et. al., 1982)' | |
| 8.BE.35 | Chlorophoenicite | (Mn,Mg)3Zn2(AsO4)(OH,O)6 |
| 8.BE.35 | Magnesiochlorophoenicite | (Mg,Mn)3Zn2(AsO4)(OH,O)6 |
| 8.BE.40 | Gerdtremmelite | (Zn,Fe)(Al,Fe)2(AsO4)(OH)5 |
| 8.BE.45 | Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 |
| 8.BE.45 | Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x |
| 8.BE.45 | Carlfrancisite | Mn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42 |
| 8.BE.45 | Arakiite | (Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 |
| 8.BE.50 | Synadelphite | Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O |
| 8.BE.55 | Holdenite | (Mn2+,Mg)6Zn3(AsO4)2(SiO4)(OH)8 |
| 8.BE.60 | Kolicite | Mn2+7Zn4(AsO4)2(SiO4)2(OH)8 |
| 8.BE.65 | Sabelliite | (Cu,Zn)2Zn(AsO4,SbO4)(OH)3 |
| 8.BE.70 | Jarosewichite | Mn2+3Mn3+(AsO4)(OH)6 |
| 8.BE.75 | Theisite | Cu5Zn5(AsO4,SbO4)2(OH)14 |
| 8.BE.80 | Coparsite | Cu4(AsO4,VO4)O2Cl |
| 8.BE.85 | Waterhouseite | Mn2+7(PO4)2(OH)8 |
| 8.BE.90 | Vasilseverginite | Cu9O4(AsO4)2(SO4)2 |
Fluorescence of Mcgovernite
None.
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
None.
Internet Links for Mcgovernite
mindat.org URL:
https://www.mindat.org/min-2614.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Mcgovernite
Reference List:
Palache, C., Bauer, L. H. (1927) McGovernite, a new mineral from Sterling Hill, New Jersey. American Mineralogist, 12 (10) 373-374
Wuensch, Berhhardt J. (1960) The crystallography of mcgovernite, a complex arsenosilicate. American Mineralogist, 45 (9-10) 937-945
Moore, Paul B., Araki, Takaharu (1978) Hematolite: a complex dense-packed sheet structure. American Mineralogist, 63 (1-2) 150-159
Dunn, Pete J., Nelen, Joseph A. (1980) Kraisslite and mcgovernite: new chemical data. American Mineralogist, 65 (9-10) 957-960
Dunn, Pete J., Francis, Carl A., Innes, John (1988) A mcgovernite-like mineral and leucophoenicite from the Kombat mine, Namibia. American Mineralogist, 73 (9-10) 1182-1185
Hawthorne, Frank C. (2018) Long-range and short-range cation order in the crystal structures of carlfrancisite and mcgovernite. Mineralogical Magazine, 82 (5) 1101-1118 doi:10.1180/minmag.2017.081.098
Localities for Mcgovernite
Showing 1 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.
USA (TL) | |
| Palache (1935) +1 other reference |
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Sterling Mine, Sterling Hill, Ogdensburg, Sussex County, New Jersey, USA