Gerstmannite
A valid IMA mineral species
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About Gerstmannite
Ewald Gerstmann
Formula:
MnMgZn(SiO4)(OH)2
Colour:
White to very pale pink.
Lustre:
Sub-Adamantine, Vitreous, Silky
Hardness:
4½
Specific Gravity:
3.68
Crystal System:
Orthorhombic
Name:
Named in 1977 by Paul Brian Moore and Takaharu Araki after Mr. Ewald "The Dutchman" Gerstmann [September 19, 1918 in Bremerhaven, Germany - December 14, 2005, Andover, New Jersey], stationary engineer, mineral dealer, and avid collector of Franklin Mining District minerals. Operator of a private mineral museum and collectors' gathering spot at Franklin, NJ, for many years. The Gerstmann mineral collection was donated to the Franklin Mineral Museum.
This page provides mineralogical data about Gerstmannite.
Unique Identifiers
Mindat ID:
1685
Long-form identifier:
mindat:1:1:1685:4
GUID
(UUID V4):
(UUID V4):
ba68a504-cc4f-417c-bb38-e2d987eab91a
IMA Classification of Gerstmannite
Approved
IMA Formula:
Mn2+MgZn(SiO4)(OH)2
Approval year:
1975
Classification of Gerstmannite
9.AE.25
9 : SILICATES (Germanates)
A : Nesosilicates
E : Nesosilicates with additional anions (O,OH,F,H2O); cations in tetrahedral [4] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
E : Nesosilicates with additional anions (O,OH,F,H2O); cations in tetrahedral [4] coordination
52.2.1.4
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
2 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
2 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
14.7.21
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
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 |
|---|---|---|
| Gmn | 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 Gerstmannite
Sub-Adamantine, Vitreous, Silky
Transparency:
Translucent, Opaque
Comment:
silky when matted
Colour:
White to very pale pink.
Streak:
white
Hardness:
4½ on Mohs scale
Cleavage:
Distinct/Good
good on {010}
good on {010}
Density:
3.68(2) g/cm3 (Measured) 3.66 g/cm3 (Calculated)
Optical Data of Gerstmannite
Type:
Biaxial (-)
RI values:
nα = 1.655(2) nβ = 1.657(2) nγ = 1.678(2)
2V:
Measured: 50° to 60°, Calculated: 36°
Max Birefringence:
δ = 0.023
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
weak
Chemistry of Gerstmannite
Mindat Formula:
MnMgZn(SiO4)(OH)2
Common Impurities:
Fe,Na
Crystallography of Gerstmannite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 8.185(7) Å, b = 18.65(2) Å, c = 6.256(6) Å
Ratio:
a:b:c = 0.439 : 1 : 0.335
Unit Cell V:
954.98 ų (Calculated from Unit Cell)
Z:
8
Comment:
Space Group: Bbcm
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0000554 | Gerstmannite | Moore P B, Araki T (1977) Gerstmannite, a new zinc silicate mineral and a novel cubic close-packed oxide structure American Mineralogist 62 51-59 |  | 1977 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.598 Å | (100) |
| 9.326 Å | (85) |
| 3.418 Å | (80) |
| 2.758 Å | (75) |
| 2.332 Å | (75) |
| 2.983 Å | (60) |
| 4.806 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-𝑇 alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Gerstmannite
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, 126484; National Museum of Natural History, Washington, D.C., USA, 135926, 137021.
Associated Minerals at Type Locality:
Reference:
Moore, P.B., Araki, T. (1977) Gerstmannite, a new zinc silicate mineral and a novel cubic close-packed oxide structure. American Mineralogist 62, 51-59.
Synonyms of Gerstmannite
Other Language Names for Gerstmannite
Related Minerals - Strunz-mindat Grouping
| 9.AE.05 | Beryllite | Be3(SiO4)(OH)2 · H2O |
| 9.AE.10 | Euclase | BeAl(SiO4)(OH) |
| 9.AE.15 | Sverigeite | NaMnMgSnBe2(SiO4)3(OH) |
| 9.AE.20 | Hodgkinsonite | Mn2+Zn2(SiO4)(OH)2 |
| 9.AE.30 | Clinohedrite | CaZn(SiO4) · H2O |
| 9.AE.35 | Stringhamite | CaCu(SiO4) · H2O |
| 9.AE.40 | Katoptrite | (Mn2+,Mg)13(Al,Fe3+)4Sb5+2(SiO4)2O20 |
| 9.AE.45 | Yeatmanite | Zn6Mn2+9Sb5+2(SiO4)4O12 |
| 9.AE.50 | Sphaerobertrandite | Be3(SiO4)(OH)2 |
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.
Internet Links for Gerstmannite
mindat.org URL:
https://www.mindat.org/min-1685.html
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References for Gerstmannite
Localities for Gerstmannite
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) | |
| Moore et al. (1977) +1 other reference |
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Sterling Mine, Sterling Hill, Ogdensburg, Sussex County, New Jersey, USA