Laihunite
A valid IMA mineral species
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About Laihunite
Formula:
(Fe2+0.5◻0.5)Fe3+[SiO4]
Colour:
Dark brown, black
Lustre:
Metallic, Sub-Metallic
Hardness:
5½ - 6½
Specific Gravity:
3.967
Crystal System:
Monoclinic
Member of:
Name:
After the type locality, Laihe Fe deposit, near Laihe village, Qianshan District, Anshan Prefecture, Liaoning Province, China.
Olivine Group.
Corresponds to a strongly oxidised, vacancy-bearing fayalite.
The "polytypes" 1M, 2M and 3M seem to be distinct intermediate phases (between laihunite and fayalite) with defined stoichiometries (Xu et al., 2014): 2M has a 1:1 ratio and 3M a 1:0.5 ratio.
The previously reported monoclinic symmetry for the 3-layer laihunite may be an artifact due to overlapping diffraction spots from both, the laihunite-3Or and the laihunite-1M.
Corresponds to a strongly oxidised, vacancy-bearing fayalite.
The "polytypes" 1M, 2M and 3M seem to be distinct intermediate phases (between laihunite and fayalite) with defined stoichiometries (Xu et al., 2014): 2M has a 1:1 ratio and 3M a 1:0.5 ratio.
The previously reported monoclinic symmetry for the 3-layer laihunite may be an artifact due to overlapping diffraction spots from both, the laihunite-3Or and the laihunite-1M.
Unique Identifiers
Mindat ID:
2312
Long-form identifier:
mindat:1:1:2312:8
GUID
(UUID V4):
(UUID V4):
545da2a4-8d53-4b85-978d-7676215b9850
IMA Classification of Laihunite
Approved
IMA Formula:
(Fe3+,Fe2+,◻)2(SiO4)
First published:
1976
Classification of Laihunite
9.AC.05
9 : SILICATES (Germanates)
A : Nesosilicates
C : Nesosilicates without additional anions; cations in octahedral [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
C : Nesosilicates without additional anions; cations in octahedral [6] coordination
51.3.1.5
51 : NESOSILICATES Insular SiO4 Groups Only
3 : Insular SiO4 Groups Only with all cations in octahedral [6] coordination
51 : NESOSILICATES Insular SiO4 Groups Only
3 : Insular SiO4 Groups Only with all cations in octahedral [6] coordination
14.19.3
14 : Silicates not Containing Aluminum
19 : Silicates of Fe
14 : Silicates not Containing Aluminum
19 : Silicates of Fe
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 |
|---|---|---|
| Lai | 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 Laihunite
Metallic, Sub-Metallic
Transparency:
Opaque
Colour:
Dark brown, black
Streak:
Brown, light
Hardness:
5½ - 6½ on Mohs scale
Hardness:
VHN100=617 - 833 - Vickers
Cleavage:
Perfect
Perfect on {100} and {010}, two less perfect ~ perpendicular to {100} and intersecting at 60 degrees
Perfect on {100} and {010}, two less perfect ~ perpendicular to {100} and intersecting at 60 degrees
Density:
3.967 g/cm3 (Measured) 4.11 g/cm3 (Calculated)
Optical Data of Laihunite
Anisotropism:
weak
Colour in reflected light:
gray
Pleochroism:
Weak
Comments:
Gray to grayish black.
Chemistry of Laihunite
Mindat Formula:
(Fe2+0.5◻0.5)Fe3+[SiO4]
Elements listed:
Common Impurities:
Mg,Ca
Crystallography of Laihunite
Polytype:
Formula:
Crystal System:
Class (H-M)
Space Group:
Space Group Setting:
Cell Parameters:
Ratio:
Unit Cell Volume (calc):
Z:
| Laihunite-1M | Laihunite-2M | Laihunite-3M |
|---|---|---|
| Fe2+1 Fe3+2◻1(SiO4)2 | ||
| Monoclinic | Monoclinic | |
| 2/m - Prismatic | 2/m - Prismatic | |
| P21/b | P21/b | |
| P21/b | P21/b | |
| a = 4.80 Å, b = 10.20 Å, c = 5.80 Å β = 91.39° | a = 4.805(2) Å, b = 10.189(9) Å, c = 17.403(9) Å β = 91.0(2)° | |
| a:b:c = 0.471 : 1 : 0.569 | a:b:c = 0.472 : 1 : 1.708 | |
| V 283.88 ų (Calculated from Unit Cell) | V 851.89 ų (Calculated from Unit Cell) | |
| 12 |
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0001057 | Laihunite | Shen B, Tamada O, Kitamura M, Morimoto N (1986) Superstructure of laihunite-3M (_.40Fe.80Fe.80SiO4) Fe1B-y coordinate changed by Tamada (Aug, 2001) American Mineralogist 71 1455-1460 |  | 1986 | 0 | 293 | |
| 0011976 | Laihunite | Ferrifayalite Research Group (1976) Ferrifayalite and its crystal structure Acta Geologica Sinica 50 161-175 | 1976 | Liaoning Province, China | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.488 Å | (10b) |
| 2.521 Å | (10) |
| 2.774 Å | (9) |
| 1.745 Å | (8) |
| 2.405 Å | (7) |
| 2.246 Å | (7) |
| 2.175 Å | (6) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Laihunite
Place of Conservation of Type Material:
n.d.
Geological Setting of Type Material:
Precambrian metamorphic iron deposit.
Associated Minerals at Type Locality:
Reference:
Laihunite Research Group, Guiyang Institute of Geochemistry, Academia Sinica and 101 Geological Team of Liaoning, Metallurgical and Geological Prospecting Company (1976): Laihunite - a new iron silicate mineral. Geochimica 1976(2), 95-103 (in Chinese with English abstract).
Synonyms of Laihunite
Other Language Names for Laihunite
Relationship of Laihunite to other Species
Member of:
Other Members of this group:
| Calcio-olivine | Ca2SiO4 | Orth. mmm (2/m 2/m 2/m) |
| Fayalite | Fe2+2SiO4 | Orth. mmm (2/m 2/m 2/m) |
| Forsterite | Mg2SiO4 | Orth. mmm (2/m 2/m 2/m) |
| Glaucochroite | CaMn2+SiO4 | Orth. mmm (2/m 2/m 2/m) |
| Kirschsteinite | CaFe2+SiO4 | Orth. mmm (2/m 2/m 2/m) : Pnma |
| Liebenbergite | Ni2SiO4 | Orth. mmm (2/m 2/m 2/m) |
| Monticellite | CaMgSiO4 | Orth. mmm (2/m 2/m 2/m) |
| Tephroite | Mn2+2SiO4 | Orth. mmm (2/m 2/m 2/m) : Pnma |
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 9.AC. | Ahrensite | SiFe2O4 |
| 9.AC. | Poirierite | Mg2SiO4 |
| 9.AC.05 | Fayalite | Fe2+2SiO4 |
| 9.AC.05 | Forsterite | Mg2SiO4 |
| 9.AC.05 | Glaucochroite | CaMn2+SiO4 |
| 9.AC.05 | Kirschsteinite | CaFe2+SiO4 |
| 9.AC.05 | Liebenbergite | Ni2SiO4 |
| 9.AC.05 | Tephroite | Mn2+2SiO4 |
| 9.AC.10 | Monticellite | CaMgSiO4 |
| 9.AC.15 | Brunogeierite | Ge4+Fe2+2O4 |
| 9.AC.15 | Ringwoodite | (Mg,Fe2+)2SiO4 |
| 9.AC.20 | Chesnokovite | Na2[SiO2(OH)2] · 8H2O |
Other Information
Notes:
Moderately magnetic and electromagnetic
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 Laihunite
mindat.org URL:
https://www.mindat.org/min-2312.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
References for Laihunite
Localities for Laihunite
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.
Antarctica | |
| Ling et al. (2015) |
| Gyollai et al. (2016) |
Austria | |
| Kolitsch et al. (2019) |
| Kolitsch et al. (2012) |
China (TL) | |
| Laihunite Research Group et al. (1976) |
France | |
| C. Lemanski (re-entry of lost Mindat data) |
Germany | |
| Blaß et al. (1995) |
Japan | |
| SUENO et al. (2002) |
| SUENO et al. (2002) |
| Kondo et al (1984) |
| Knut Eldjarn Collection |
Russia | |
| Cesnokov et al. (1998) |
USA | |
| Eckel et al. (1997) |
| [AmMin 84:196] | |
| Eckel et al. (1997) |
| Microprobe Vol 9 #4 +1 other reference |
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Caspar quarry, Ettringen, Vordereifel, Mayen-Koblenz, Rhineland-Palatinate, Germany