Greenalite
A valid IMA mineral species - grandfathered
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About Greenalite
Formula:
(Fe2+,Fe3+)2-3Si2O5(OH)4
Colour:
green, light yellow-green
Lustre:
Dull, Earthy
Hardness:
2½
Specific Gravity:
2.85 - 3.15
Crystal System:
Monoclinic
Member of:
Name:
Named in allusion to its green colour.
Type Locality:
Unique Identifiers
Mindat ID:
1745
Long-form identifier:
mindat:1:1:1745:5
Similar Names
| Granulite | A rock classification type |
IMA Classification of Greenalite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
(Fe2+,Fe3+)2-3Si2O5(OH)4
Classification of Greenalite
9.ED.15
9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets
71.1.2b.4
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
1 : Sheets of 6-membered rings with 1:1 layers
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
1 : Sheets of 6-membered rings with 1:1 layers
14.19.6
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.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Gre | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Gre | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
| Gre | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Gre | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
| Gre | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30 |
Physical Properties of Greenalite
Dull, Earthy
Transparency:
Translucent
Colour:
Green, light yellow-green
Streak:
Greenish-gray
Hardness:
2½ on Mohs scale
Density:
2.85 - 3.15 g/cm3 (Measured)
Optical Data of Greenalite
Type:
Biaxial (+)
RI values:
nα = 1.65 - 1.675 nβ = 1.674 nγ = 1.674
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 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.
No measured or calculated 2V is on file for this mineral, so the value used here (180°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (180°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
weak
Pleochroism:
Visible
Comments:
Pale yellow to green
Comments:
Isotropic when fine grained. n = 1.670
Chemistry of Greenalite
Mindat Formula:
(Fe2+,Fe3+)2-3Si2O5(OH)4
Element Weights:
Elements listed:
Common Impurities:
Al,Mn,Mg
Crystallography of Greenalite
Polytype:
Formula:
Crystal System:
Class (H-M)
Space Group:
Space Group Setting:
Cell Parameters:
Ratio:
Unit Cell Volume (calc):
Z:
Comment:
| Greenalite-1A | Greenalite-1M | Greenalite-2Å | Greenalite-2M1 | Greenalite-3Å | Greenalite-3R |
|---|---|---|---|---|---|
| (Fe2+,Fe3+)2-3Si2O5(OH)4 | (Fe2+,Fe3+)2-3Si2O5(OH)4 | (Fe2+,Fe3+)2-3Si2O5(OH)4 | (Fe2+,Fe3+)2-3Si2O5(OH)4 | (Fe2+,Fe3+)2-3Si2O5(OH)4 | (Fe2+,Fe3+)2-3Si2O5(OH)4 |
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Big Balls | Small Balls | Just Balls | Spacefill
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Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
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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) |
|---|---|---|---|---|---|---|---|
| 0000136 | Greenalite | Shirozu H, Bailey S W (1965) Chlorite polytypism: III. Crystal structure of an orthohexagonal iron chlorite American Mineralogist 50 868-885 |  | 1965 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.12 Å | (80) |
| 3.559 Å | (80) |
| 2.849 Å | (20) |
| 2.571 Å | (100) |
| 2.184 Å | (40) |
| 1.593 Å | (60) |
| 1.553 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Near-surface Processes | |
| 21 : Chemically precipitated carbonate, phosphate, iron formations | |
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Greenalite
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 91160, 124953.
Geological Setting of Type Material:
banded iron formation
Associated Minerals at Type Locality:
Other Language Names for Greenalite
Relationship of Greenalite to other Species
Member of:
Other Members of Kaolinite-Serpentine Group:
| Kaolinite Subgroup | Al2Si2O5(OH)4 | |
| Manandonite | Li2Al4(Si2AlB)O10(OH)8 | Orth. 222 : C2221 |
| Odinite | (Fe,Mg,Al,Fe,Ti,Mn)2.4((Si,Al)2O5)(OH)4 | Mon. m : Bm |
| Serpentine Subgroup | D3[Si2O5](OH)4 |
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 10 photos of Greenalite associated with Galena | PbS |
| 6 photos of Greenalite associated with Siderite | FeCO3 |
| 4 photos of Greenalite associated with Quartz | SiO2 |
| 2 photos of Greenalite associated with Fluorite | CaF2 |
| 2 photos of Greenalite associated with 'Chalcedony' | SiO2 |
| 2 photos of Greenalite associated with Anglesite | PbSO4 |
| 2 photos of Greenalite associated with 'Chert' | |
| 1 photo of Greenalite associated with 'Monheimite' | (Zn,Fe)CO3 |
| 1 photo of Greenalite associated with Chalcopyrite | CuFeS2 |
| 1 photo of Greenalite associated with 'Blue Chalcedony' | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 9.ED. | 'Clinochrysotile' | Mg3(Si2O5)(OH)4 |
| 9.ED.05 | Dickite | Al2(Si2O5)(OH)4 |
| 9.ED.05 | Nacrite | Al2(Si2O5)(OH)4 |
| 9.ED.05 | Kaolinite | Al2(Si2O5)(OH)4 |
| 9.ED.05 | Odinite | (Fe,Mg,Al,Fe,Ti,Mn)2.4((Si,Al)2O5)(OH)4 |
| 9.ED.10 | Halloysite | Al2Si2O5(OH)4 · n(H2O) |
| 9.ED.10 | Hisingerite | Fe3+2(Si2O5)(OH)4 · 2H2O |
| 9.ED.10 | 'Hydrohalloysite' | Al2Si2O5(OH)4 · 2H2O |
| 9.ED.15 | Antigorite | Mg3(Si2O5)(OH)4 |
| 9.ED.15 | Brindleyite | (Ni,Al)3(Si,Al)2O5(OH)4 |
| 9.ED.15 | Fraipontite | (Zn,Al)3((Si,Al)2O5)(OH)4 |
| 9.ED.15 | Népouite | Ni3Si2O5(OH)4 |
| 9.ED.15 | Pecoraite | Ni3(Si2O5)(OH)4 |
| 9.ED.15 | Guidottiite | Mn2Fe3+(Fe3+SiO5)(OH)4 |
| 9.ED.15 | Lizardite | Mg3(Si2O5)(OH)4 |
| 9.ED.15 | Berthierine | (Fe2+,Fe3+,Al)3(Si,Al)2O5(OH)4 |
| 9.ED.15 | Kellyite | Mn2+2Al(AlSiO5)(OH)4 |
| 9.ED.15 | Cronstedtite | Fe2+2Fe3+((Si,Fe3+)2O5)(OH)4 |
| 9.ED.15 | Caryopilite | Mn2+3Si2O5(OH)4 |
| 9.ED.15 | Amesite | Mg2Al(AlSiO5)(OH)4 |
| 9.ED.15 | Manandonite | Li2Al4(Si2AlB)O10(OH)8 |
| 9.ED.20 | Chrysocolla | Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O, x < 1 |
| 9.ED.20 | Neotocite | (Mn,Fe)SiO3 · H2O (?) |
| 9.ED.20 | Allophane | (Al2O3)(SiO2)1.3-2 · 2.5-3H2O |
| 9.ED.20 | Imogolite | Al2SiO3(OH)4 |
| 9.ED.25 | Bismutoferrite | Fe3+2Bi(SiO4)2(OH) |
| 9.ED.25 | Chapmanite | Fe3+2Sb3+(Si2O5)O3(OH) |
| 9.ED.30 | 'Pianlinite' | Al2Si2O6(OH)2 |
Other Information
Notes:
Moderately magnetic.
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 Greenalite
mindat.org URL:
https://www.mindat.org/min-1745.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Greenalite
Reference List:
Gruner, John W. (1936) The structure and chemical composition of greenalite. American Mineralogist, 21 (7) 449-455
Brindley, G. W., Youell, R. F. (1953) Ferrous chamosite and ferric chamosite. Mineralogical Magazine and Journal of the Mineralogical Society, 30 (220) 57-70 doi:10.1180/minmag.1953.030.220.07
STEADMAN, R., YOUELL, R. F. (1958) Mineralogy and Crystal Structure of Greenalite. Nature, 181 (4601). 45 doi:10.1038/181045a0
Gole, Martin J. (1980) Mineralogy and petrology of very-low-metamorphic grade Archaean banded iron-formations, Weld Range, Western Australia. American Mineralogist, 65 (1-2) 8-25
Bayliss, Peter (1981) Unit cell data of serpentine group minerals. Mineralogical Magazine, 44 (334) 153-156 doi:10.1180/minmag.1981.044.334.06
Baker, J. H. (1985) Greenalite, Mg-rich minnesotaite and stilpnomelane from the Ösjöberg and Sirsjöberg iron-ore mines, Hjulsjö, W. Bergslagen, Sweden. Mineralogical Magazine, 49 (353) 611-613 doi:10.1180/minmag.1985.049.353.18
Papike, J. J. (1988) Chemistry of the rock‐forming silicates: Multiple‐chain, sheet, and framework structures. Reviews of Geophysics, 26 (3). 407-444 doi:10.1029/rg026i003p00407
Wiewióra, A. (1990) Crystallochemical classifications of phyllosilicates based on the unified system of projection of chemical composition: III. The serpentine-kaolin group. Clay Minerals, 25 (1) 93-98 doi:10.1180/claymin.1990.025.1.10
Rasmussen, Birger, Muhling, Janet R., Suvorova, Alexandra, Krapež, Bryan (2017) Greenalite precipitation linked to the deposition of banded iron formations downslope from a late Archean carbonate platform. Precambrian Research, 290. 49-62 doi:10.1016/j.precamres.2016.12.005
Tutolo, Benjamin, Evans, Bernard, Kuehner, Scott (2019) Serpentine–Hisingerite Solid Solution in Altered Ferroan Peridotite and Olivine Gabbro. Minerals, 9 (1) 47 doi:10.3390/min9010047 (with data on high-Si greenalite)
Ghosh, Rupam (2020) Authigenic precipitation of ferric oxyhydroxides and greenalite in Archean oceans. Chemical Geology, 552. 119777 doi:10.1016/j.chemgeo.2020.119777
Muhling, Janet R., Rasmussen, Birger (2020) Widespread deposition of greenalite to form Banded Iron Formations before the Great Oxidation Event. Precambrian Research, 339. 105619 doi:10.1016/j.precamres.2020.105619
Rasmussen, B., Muhling, J.R., Fischer, W.W. (2021) Greenalite Nanoparticles in Alkaline Vent Plumes as Templates for the Origin of Life. Astrobiology, 21 (2) 246-259 doi:10.1089/ast.2020.2270
Rasmussen, B.; Muhling, J.R.; Krapež, B. (2021) Greenalite and its role in the genesis of early Precambrian iron formations – A review. Earth-Science Reviews, 217. 103613 doi:10.1016/j.earscirev.2021.103613
Hinz, Isaac L., Nims, Christine, Theuer, Samantha, Templeton, Alexis S., Johnson, Jena E. (2021) Ferric iron triggers greenalite formation in simulated Archean seawater. Geology, 49 (8) 905-910 doi:10.1130/g48495.1
Rasmussen, Birger; Muhling, Janet R. (2021) Development of a greenalite-silica shuttle during incursions of hydrothermal vent plumes onto Neoarchean shelf, Hamersley region, Australia. Precambrian Research, 353. 106003 doi:10.1016/j.precamres.2020.106003
Rasmussen, Birger; Muhling, Janet R.; Tosca, Nicholas J. (2024) Nanoparticulate apatite and greenalite in oldest, well-preserved hydrothermal vent precipitates. Science Advances, 10 (4). eadj4789 doi:10.1126/sciadv.adj4789
Nke, Ansahmbom Y., Tsikos, Harilaos, Mason, Paul R.D., Mhlanga, Xolane, Tostevin, Rosalie (2024) A seawater origin for greenalite in iron formation. Earth and Planetary Science Letters, 643. 118917 doi:10.1016/j.epsl.2024.118917
Rasmussen, Birger; Fischer, Woodward; Duzdevich, Daniel (2025) Greenalite: A Template Fit for Life? Elements, 21 (3). 197-203 doi:10.2138/gselements.21.3.197
Tosca, Nicholas J.; Jiang, Clancy Zhijian; Tutolo, Benjamin M. (2025) The Precambrian Greenalite Factory. Elements, 21 (3). 191-196 doi:10.2138/gselements.21.3.191
Rasmussen, Birger; Muhling, Janet R.; Tosca, Nicholas J. (2025) Greenalite: A Tiny Crystal with a Big Story. Elements, 21 (3). 163-169 doi:10.2138/gselements.21.3.163
Localities for Greenalite
Showing 82 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.
Australia | |
| Birch (1999) |
| Skirrow (1993) |
| Miningdataonline +1 other reference |
| Kwak et al. (1988) |
| Zolensky et al. (1987) |
| Gole (1980) |
| Angerer et al. (2022) |
| Mining Annual Review (1985) |
| Lascelles (2006) |
| Gole (1980) |
Bolivia | |
| A.R. Kampf |
Brazil | |
| Vale SA |
| Huang et al. (2022) |
Canada | |
| |
| Grice et al. (1984) +1 other reference |
| Klein et al. (1976) |
| Robertson (1976) |
| Vos |
| Galley et al. (1995) +1 other reference |
| Klein et al. (1976) |
China | |
| Zeng et al. (1999) |
| Wang et al. (2024) |
Colombia | |
| Castrillón et al. (2023) |
Czech Republic | |
| Novotný et al. (2003) |
Finland | |
| Paakkola |
France | |
| Chauris (2014) |
| Chauris (2014) |
Ghana | |
| Addae et al. (2026) |
Iran | |
| Nezafati et al. (2017) |
| Nezafati et al. (2017) | |
Italy | |
| Carbone et al. (2002) |
| D'Angeli et al. (2018) |
Japan | |
| Matsubara et al. (1989) |
| - (n.d.) |
| Kato (2010) |
| - (n.d.) |
Mexico | |
| Stone +1 other reference |
Middle East | |
| Vapnik et al. (2006) | |
Norway | |
| [Greenalite-1M] Harald Folvik collection. +1 other reference |
Pacific Ocean | |
| Fryer et al. (1992) |
Romania | |
| Udubasa et al. (1996) +1 other reference |
| minerals-of-the-carpathians.eu (2008) |
Russia | |
| - (2014) |
| Mikhailova et al. (2015) |
| Bazai et al. (2009) |
| Bernard et al. (2004) |
| Bystrov et al. (2015) |
Slovakia | |
| Myšľan et al. (2025) |
South Africa | |
| Weinert (2006) |
| SIEMES (2013) |
| Fitton (2022) +1 other reference |
| Cairncross et al. (1995) | |
Spain | |
| Berbain +2 other references |
| Tánago et al. (2012) |
| Lopez (1987) |
| Garcia (2011) |
| Calvo Rebollar (2015) | |
| Lopez Garcia et al. (1987) | |
Sweden | |
| Baker (1985) |
Switzerland | |
| Dietrich (1972) |
| Stalder et al. (1998) | |
Tajikistan | |
| Sharygin et al. (2009) |
Tanzania | |
| AngloGold Ashanti Limited |
USA | |
| Dean (1995) |
| Cook et al. (1982) |
| Cook et al. (1982) | |
| Heinrich et al. (2004) |
| Thomas M. Bee specimens | |
| Heinrich et al. (2004) | |
| Heinrich et al. (2004) | |
| Heinrich et al. (2004) | |
| - (2005) |
| Heinrich et al. (2004) |
| Ransom (1974) |
| Ransom (1974) | |
| Jolliffe (1935) | |
| Ripley +4 other references |
| Muir Wood (1982) |
| Adamera Minerals |
| USGS Bul.1460:96 |
Yemen | |
| Zolensky et al. (2003) |
Quick NavTopAbout GreenaliteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence Other LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Dalnegorsk, Dalnegorsk Urban District, Primorsky Krai, Russia