Gedrite
A valid IMA mineral species - grandfathered
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About Gedrite
Gèdre, France
Formula:
◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2
The gedrite group are orthorhombic amphiboles in the magnesium-iron-manganese amphibole subgroup defined with A(Na+K+2Ca)<0.5 apfu and C(Al+Fe3++2Ti)>1 apfu
Gedrite is defined with Mg2+ as the dominant cation both in the B and C2+ positions and Al in the C3+ position.
Gedrite is defined with Mg2+ as the dominant cation both in the B and C2+ positions and Al in the C3+ position.
Colour:
Pale greenish-grey to brown
Lustre:
Vitreous
Hardness:
5½ - 6
Specific Gravity:
3.15 - 3.26
Crystal System:
Orthorhombic
Member of:
Name:
Named after the type locality at Gèdres, Héas Valley, France.
Widespread in medium- to high-grade metamorphic rocks; in metasomatized contact metamorphic rocks.
Forms a series with ferro-gedrite.
Visit gemdat.org for gemological information about Gedrite.
Forms a series with ferro-gedrite.
Visit gemdat.org for gemological information about Gedrite.Unique Identifiers
Mindat ID:
1665
Long-form identifier:
mindat:1:1:1665:6
IMA Classification of Gedrite
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Redefined by the IMA
IMA Formula:
◻Mg2(Mg3Al2)(Si6Al2)O22(OH)2
First published:
1836
Approval history:
Grandfathered.
Redefined by IMA in 2012.
Redefined by IMA in 2012.
Type description reference:
Classification of Gedrite
9.DD.05
9 : SILICATES (Germanates)
D : Inosilicates
D : Inosilicates with 2-periodic double chains, Si4O11; Orthoamphiboles
9 : SILICATES (Germanates)
D : Inosilicates
D : Inosilicates with 2-periodic double chains, Si4O11; Orthoamphiboles
66.1.2.5
66 : INOSILICATES Double-Width,Unbranched Chains,(W=2)
1 : Amphiboles - Mg-Fe-Mn-Li subgroup
66 : INOSILICATES Double-Width,Unbranched Chains,(W=2)
1 : Amphiboles - Mg-Fe-Mn-Li subgroup
16.19.18
16 : Silicates Containing Aluminum and other Metals
19 : Aluminosilicates of Fe and Mg
16 : Silicates Containing Aluminum and other Metals
19 : Aluminosilicates of Fe and Mg
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 |
|---|---|---|
| Ged | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Ged | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Ged | 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 |
| Ged | 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 |
| Ged | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Gedrite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Pale greenish-grey to brown
Streak:
White
Hardness:
5½ - 6 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {210}, imperfect on {100}, {001}
Perfect on {210}, imperfect on {100}, {001}
Density:
3.15 - 3.26 g/cm3 (Measured) 3.25(7) g/cm3 (Calculated)
Optical Data of Gedrite
Type:
Biaxial (-)
RI values:
nα = 1.671 nβ = 1.681 nγ = 1.69
2V:
Measured: 70° to 90°, Calculated: 86°
Max. Birefringence:
δ = 0.019
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.
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.
Surface Relief:
Moderate
Dispersion:
r > v strong
Pleochroism:
Weak
Comments:
Browns, yellow, gray
Chemistry of Gedrite
Mindat Formula:
◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2
The gedrite group are orthorhombic amphiboles in the magnesium-iron-manganese amphibole subgroup defined with A(Na+K+2Ca)<0.5 apfu and C(Al+Fe3++2Ti)>1 apfu
Gedrite is defined with Mg2+ as the dominant cation both in the B and C2+ positions and Al in the C3+ position.
The gedrite group are orthorhombic amphiboles in the magnesium-iron-manganese amphibole subgroup defined with A(Na+K+2Ca)<0.5 apfu and C(Al+Fe3++2Ti)>1 apfu
Gedrite is defined with Mg2+ as the dominant cation both in the B and C2+ positions and Al in the C3+ position.
Element Weights:
Common Impurities:
Mn,Ca,Ti,Na,K
Crystallography of Gedrite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 18.59 Å, b = 17.89 Å, c = 5.3 Å
Ratio:
a:b:c = 1.039 : 1 : 0.296
Unit Cell V:
1,762.65 ų (Calculated from Unit Cell)
Comment:
Space Group: Pnma:
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) |
|---|---|---|---|---|---|---|---|
| 0000215 | Gedrite | Papike J J, Ross M (1970) Gedrites: Crystal structures and intracrystalline cation distributions sample 001 American Mineralogist 55 1945-1972 |  | 1970 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.06 Å | (100) |
| 8.27 Å | (80) |
| 3.23 Å | (70) |
| 8.97 Å | (50) |
| 4.48 Å | (40) |
| 3.65 Å | (40) |
| 3.35 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 9 : Lava/xenolith minerals (hornfels, sanidinite facies) | |
| Near-surface Processes | |
| 26 : Hadean detrital minerals | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) |
Type Occurrence of Gedrite
Synonyms of Gedrite
Other Language Names for Gedrite
Varieties of Gedrite
| Bidalotite | Described in 1937 as a new species of "orthopyroxene", with lilac colour. |
| Snarumite | Probably an iron-free variety of gedrite. |
Relationship of Gedrite to other Species
Member of:
Other Members of Gedrite Root Name Group:
| Ferro-gedrite | ◻{Fe2+2}{Fe2+3Al2}(Al2Si6O22)(OH)2 | Orth. mmm (2/m 2/m 2/m) : Pnma |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
| 25 photos of Gedrite associated with Almandine | Fe2+3Al2(SiO4)3 |
| 23 photos of Gedrite associated with Albite | Na(AlSi3O8) |
| 19 photos of Gedrite associated with Quartz | SiO2 |
| 10 photos of Gedrite associated with Magnetite | Fe2+Fe3+2O4 |
| 6 photos of Gedrite associated with Sapphirine | Mg4(Mg3Al9)O4[Si3Al9O36] |
| 4 photos of Gedrite associated with Anthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| 3 photos of Gedrite associated with Anthophyllite-Gedrite Series | |
| 3 photos of Gedrite associated with Rutile | TiO2 |
| 3 photos of Gedrite associated with Sulphotsumoite | Bi3Te2S |
| 3 photos of Gedrite associated with Cerite-(CeCa) | (Ce7Ca2)◻Mg(SiO4)3(SiO3OH)4(OH)3 |
Related Minerals - Strunz-mindat Grouping
| 9.DD.05 | Suenoite | ◻Mn2Mg5Si8O22(OH)2 |
| 9.DD.05 | Proto-ferro-anthophyllite | ◻{Fe2+2}{Fe2+5}(Si8O22)(OH)2 |
| 9.DD.05 | Proto-ferro-suenoite | ◻{Mn2+2}{Fe2+5}(Si8O22)(OH)2 |
| 9.DD.05 | Lavinskyite | K(LiCu)Cu6(Si4O11)2(OH)4 |
| 9.DD.05 | Papikeite | NaMg2(Mg3Al2}(Al3Si5O22)(OH)2 |
| 9.DD.05 | Holmquistite | ◻{Li2}{Mg3Al2}(Si8O22)(OH)2 |
| 9.DD.05 | Sodic-anthophyllite | {Na}{Mg2}{Mg5}(AlSi7O22)(OH)2 |
| 9.DD.05 | Sodic-ferro-anthophyllite | {Na}{Fe2+2}{Fe2+5}(AlSi7O22)(OH)2 |
| 9.DD.05 | Ferro-papikeite | NaFe2+2(Fe2+3Al2)(Si5Al3O22)(OH)2 |
| 9.DD.05 | Ferro-anthophyllite | ◻{Fe2+2}{Fe2+5}(Si8O22)(OH)2 |
| 9.DD.05 | Proto-anthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| 9.DD.05 | Ferro-gedrite | ◻{Fe2+2}{Fe2+3Al2}(Al2Si6O22)(OH)2 |
| 9.DD.05 | Ferri-holmquistite | ◻{Li2}{Mg3Fe3+2}(Si8O22)(OH)2 |
| 9.DD.05 | Ferro-ferri-holmquistite | ◻{Li2}{Fe2+3Fe3+2}(Si8O22)(OH)2 |
| 9.DD.05 | Ferro-holmquistite | ◻{Li2}{Fe2+3Al2}(Si8O22)(OH)2 |
| 9.DD.05 | Anthophyllite | ◻{Mg2}{Mg5}(Si8O22)(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.
Gedrite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Gedrite
mindat.org URL:
https://www.mindat.org/min-1665.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Gedrite
Reference List:
Tilley, C. E. (1939) Kyanite-Gedrite Parageneses. Geological Magazine, 76 (7) 326-330 doi:10.1017/s0016756800071223
Milton, D. J., Ito, J. (1961) Gedrite from Oxford County, Maine. American Mineralogist, 46 (5-6) 734-740
Papike, J. J., Ross, Malcolm (1970) Gedrites: Crystal structures and intracrystalline cation distributions. American Mineralogist, 55 (11-12) 1945-1972
Smelik, Eugene A., Veblen, David R. (1993) A transmission and analytical electron microscope study of exsolution microstructures and mechanisms in the orthoamphiboles anthophyllite and gedrite. American Mineralogist, 78 (5-6) 511-532
Leake, B. E., Woolley, A. R., Arps, C. E. S., Birch, W. D., Gilbert, M. C., Grice, J. D., Hawthorne, F. C., Kato, A., Kisch, H. J., Krivovochev, V. G., Linthout, K., Laird, J., Mandarino, J. A., Maresch, W. V., Nickel, E.H., Rock, N. M. S., Schumacher, J. C., Smith, D. C., Stephenson, N. C. N., Ungaretti, L., Whittaker, E. J. W., Youzhi, Gou (1997) Nomenclature of amphiboles: report of the Subcommittee on Amphiboles of the International Mineralogical Association, Commission on New Minerals and Mineral Names. The Canadian Mineralogist, 35 (1) 219-246
Champness, P. E., Rodgers, K. A. (2000) The origin of iridescence in anthophyllite-gedrite from Simiuttat, Nuuk district, southern West Greenland. Mineralogical Magazine, 64 (5). 885-889 doi:10.1180/002646100549715
Hawthorne, F. C., Oberti, R. (2006) On the classification of amphiboles. The Canadian Mineralogist, 44 (1) 1-21 doi:10.2113/gscanmin.44.1.1
Schindler, M., Sokolova, E., Abdu, Y., Hawthorne, F. C., Evans, B. W., Ishida, K. (2008) The crystal chemistry of the gedrite-group amphiboles. I. Crystal structure and site populations. Mineralogical Magazine, 72 (3) 703-730 doi:10.1180/minmag.2008.072.3.703
Localities for Gedrite
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.
Afghanistan | |
| Deer (1978) |
Algeria | |
| C. Lemanski (re-entry lost Mindat data) |
Antarctica | |
| Journal of Petrology et al. (7) |
| Yuki Mori (2017) |
Australia | |
| Preliminary sulphur isotopes report. In ... +1 other reference |
| Sheppard et al. (1995) |
| Slack et al. (1993) |
| Warren et al. (1974) |
| Vry (1994) | |
| Wilson (1977) |
| Hudson et al. (1966) +1 other reference | |
| Rubenach et al. (2002) |
| Mount Woods Inlier et al. (Honors thesis) +1 other reference |
| Bottrill et al. (2008) |
| Bottrill et al. (2008) |
| |
| Hassan (2017) |
| Ferguson (1999) |
Botswana | |
| Maier et al. (2008) |
Brazil | |
| Econ Geol (1986) +1 other reference |
| Candia et al. (1997) |
| Araujo et al. (1995) |
Canada | |
| Bristol et al. (1989) |
| Bernier (1990) | |
| Jeremie Pfister Collection |
| Charles A. Tarnocai et al. (1997) +1 other reference |
| Petersen (1986) +3 other references |
| Pan (1997) | |
| Williams (1990) |
China | |
| Guochun Zhao et al. (2004) |
| Yiming Zhao et al. (2008) |
| Songnian Lu et al. (2003) |
Finland | |
| Grew et al. (1998) |
| www.gsf.fi (2002) |
| Niskanen (2014) |
France | |
| Leblanc et al. (1987) |
| Pélisson (1989) |
| F.H. Forestier : "Les Péridotites ... +1 other reference |
| F.H. Forestier : "Les Péridotites ... +1 other reference |
| Forestier (1964) |
| F.H. Forestier : "Les Péridotites ... | |
| |
| Forestier (1964) |
| Pélisson (1989) |
| Pélisson (1989) |
| F.H. Forestier : "Les Péridotites ... |
| Forestier (1964) | |
| Forestier (1964) | |
| Wells et al. (2009) |
| Claude Laforêt |
| R. Pierrot |
| AM 63 (1978) |
Germany | |
| Walenta (1992) |
| |
| |
Greenland | |
| Bøggild (1953) |
| Uitterdijk Appel (1986) | |
| Petersen et al. (1993) | |
| J.Ralph |
| Friend (1982) |
| Bøggild (1953) +1 other reference | |
| Ackermand et al. (1983) | |
| Rodgers et al. (1996) +1 other reference | |
India | |
| B. Rama Rao and L. Rama Rao (1937) |
Italy | |
| Dalrio (1980) |
| Simon et al. (2001) +1 other reference |
| Mandarino (1996) | |
| Campostrini (2001) |
Japan | |
| |
| Jun-ichi Kitahara (1965) |
Madagascar | |
| Behier (1963) |
| Lacroix (1913) | |
New Zealand | |
| C. M. Ward (1984) |
Norway | |
| Visser (1993) |
| Kihle et al. (1992) |
| Kihle (2013) |
| Kihle (1989) |
| Touret et al. (1971) |
| Reykdal (2022) |
| Norges geologiske undersøkelse.Malmdatabasen. Skuterud Mellomgruver. Forekomst nr.21 i Modum (0623) |
| Jøsang (1966) |
| Jøsang (1966) | |
| Kullerud et al. (2019) |
| Rosenberg et al. (2000) |
| King (n.d.) |
| Wilke (1976) | |
| Nilsen (1971) |
Russia | |
| Berdnikov et al. (2023) |
| Berdnikov et al. (2023) | |
| Berdnikov et al. (2023) | |
| Lennikov et al. (2004) |
| Filimonova et al. (2008) |
| Yu.A.Kozhevnikov (2010) |
| Nikolay Serebryakov data |
| Pavel.M. Kartashov (n.d.) |
| Trunilina et al. (2024) |
| Trunilina et al. (2024) |
| Gregor Borg et al (2001) |
South Africa | |
| Contrib Mineral Petrol (1985) |
| Contrib Mineral Petrol (1985) | |
| Rozendaal et al. (2017) |
Spain | |
| Bareche (2005) |
| & locality references +1 other reference | |
| Pascual +2 other references |
| ATLANTI et al. (1983) |
| Williams (1983) |
| Calvo (2018) | |
Sri Lanka | |
| Kriegsman et al. (1999) |
Sweden | |
| Jansson (2001) |
| Lasskogen (2010) |
| Öhman et al. (2000) |
| |
| |
| |
| |
| Wilke (1976) |
| The Swedish Museum of Natural History ... | |
| 33 IGC excursion No 12 +1 other reference | |
| |
| Fullerton (2014) |
| |
| |
| Damman (1988) |
| Holtstam et al. (1999) |
| Magnusson (1929) |
| Magnusson (1929) | |
| |
| Ounchanum et al. (1987) |
Switzerland | |
| Stalder et al. (1998) |
Tajikistan | |
| Grew et al. (1998) |
UK | |
| Day (1999) |
| Day (1999) | |
| [Specimen in the Natural History Museum | |
USA | |
| - (1915) |
| Schrader (1915) |
| Schrader (1915) +2 other references | |
| Eckel et al. (1997) |
| Spry et al. (2022) |
| The Canadian Mineralogist Vol. 43 (2005) +1 other reference | |
| Eckel et al. (1997) |
| Eckel et al. (1997) | |
| Eckel et al. (1997) |
| Berke et al. (2023) |
| Spry et al. (2022) |
| Eckel et al. (1997) |
| Journal of Petrology (1991) |
| Spry et al. (2022) |
| Eckel et al. (1997) | |
| Eckel et al. (1997) |
| Eckel et al. (1997) | |
| Lundgren (1979) |
| Schooner (circa 1985) |
| Lundgren (1979) | |
| Rocks & Min.: 64:194. |
| Helms et al. (1987) |
| Hietanen |
| ... |
| ... | |
| King et al. (1994) |
| Gleba (2008) |
| Emerson (1895) |
| Emerson (1917) |
| Gobla (2012) |
| Condit et al. (2018) |
| Burger (2004) |
| Castor et al. (2004) |
| kilburn.keene.edu (n.d.) |
| Schumacher and Robinson (6) | |
| Schumacher et al. (1987) | |
| Cristofono (n.d.) |
| Wood (1996) |
| Wilson et al. (1978) | |
| Papike et al. (1970) | |
| Self Collected- Bruce Osborne | |
| USGS MRDS Database +1 other reference |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| - (2005) | |
| Rocks & Min. Vol. 71 (1996) |
| SPEAR (1982) |
| Dietrich (1990) |
| Kimball |
| Cordua (1998) |
Zimbabwe | |
| J. Petrology (2002) |
| Chaumba (2017) |
Quick NavTopAbout GedriteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesVarietiesRelationshipsCommon AssociatesStrunz-MindatOther InformationGedrite in petrologyInternet Links References Localities Locality List
Skisshyttan, Smedjebacken, Dalarna County, Sweden