Ferro-gedrite
A valid IMA mineral species - grandfathered
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About Ferro-gedrite
Formula:
◻{Fe2+2}{Fe2+3Al2}(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
Ferro-gedrite is defined with Fe2+ as the dominant element both in the B and C2+ positions and Al in the C3+ position.
Ferro-gedrite is defined with Fe2+ as the dominant element both in the B and C2+ positions and Al in the C3+ position.
Colour:
Pale greenish-grey to brown
Lustre:
Vitreous
Hardness:
5½ - 6
Crystal System:
Orthorhombic
Member of:
Name:
Named for its relationship to gedrite. The species was originally named ferrogedrite. The hyphen was added in 2012 by the IMA.
Unique Identifiers
Mindat ID:
1515
Long-form identifier:
mindat:1:1:1515:4
GUID
(UUID V4):
(UUID V4):
06547eb0-187e-40c4-82f5-5564b995e3d4
IMA Classification of Ferro-gedrite
Approved, 'Grandfathered' (first described prior to 1959)
IMA status notes:
Redefined by the IMA
IMA Formula:
◻Fe2+2(Fe2+3Al2)(Si6Al2)O22(OH)2
First published:
1939
Approval history:
Redefined IMA 2012 s.p.
Classification of Ferro-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
16.19.4
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 |
|---|---|---|
| Fged | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Fgd | 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 |
Physical Properties of Ferro-gedrite
Optical Data of Ferro-gedrite
Type:
Biaxial (-)
RI values:
nα = 1.642 - 1.694 nβ = 1.649 - 1.710 nγ = 1.661 - 1.722
2V:
Measured: 82° , Calculated: 76° to 80°
Max Birefringence:
δ = 0.019 - 0.028
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:
High
Dispersion:
r > v or r < v
Chemistry of Ferro-gedrite
Mindat Formula:
◻{Fe2+2}{Fe2+3Al2}(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
Ferro-gedrite is defined with Fe2+ as the dominant element 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
Ferro-gedrite is defined with Fe2+ as the dominant element both in the B and C2+ positions and Al in the C3+ position.
Common Impurities:
Ti,Mn,Ca,Na,K,F
Crystallography of Ferro-gedrite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pnma
Setting:
Pnma
Cell Parameters:
a = 18.52 Å, b = 17.94 Å, c = 5.31 Å
Ratio:
a:b:c = 1.032 : 1 : 0.296
Unit Cell V:
1,764.24 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.23 Å | (100) |
| 3.043 Å | (75) |
| 3.221 Å | (20) |
| 8.95 Å | (12) |
| 4.632 Å | (10) |
| 2.679 Å | (10) |
| 2.581 Å | (10) |
Comments:
Mt. Yakushi, Japan.
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) |
Synonyms of Ferro-gedrite
Other Language Names for Ferro-gedrite
German:Ferrogedrit
Spanish:Ferrogedrita
Relationship of Ferro-gedrite to other Species
Common Associates
Associated Minerals Based on Photo Data:
| 1 photo of Ferro-gedrite associated with Siderophyllite | KFe2+2Al(Al2Si2O10)(OH)2 |
| 1 photo of Ferro-gedrite associated with Gehlenite | Ca2Al[AlSiO7] |
| 1 photo of Ferro-gedrite associated with Chlorite Group | |
| 1 photo of Ferro-gedrite associated with Talc | Mg3Si4O10(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 9.DD.05 | Anthophyllite | ◻{Mg2}{Mg5}(Si8O22)(OH)2 |
| 9.DD.05 | Ferro-anthophyllite | ◻{Fe2+2}{Fe2+5}(Si8O22)(OH)2 |
| 9.DD.05 | Gedrite | ◻{Mg2}{Mg3Al2}(Al2Si6O22)(OH)2 |
| 9.DD.05 | Holmquistite | ◻{Li2}{Mg3Al2}(Si8O22)(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 | 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-holmquistite | ◻{Li2}{Fe2+3Al2}(Si8O22)(OH)2 |
| 9.DD.05 | Proto-anthophyllite | ◻{Mg2}{Mg5}(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 | Ferri-holmquistite | ◻{Li2}{Mg3Fe3+2}(Si8O22)(OH)2 |
| 9.DD.05 | Ferro-ferri-holmquistite | ◻{Li2}{Fe2+3Fe3+2}(Si8O22)(OH)2 |
| 9.DD.05 | Suenoite | ◻Mn2Mg5Si8O22(OH)2 |
| 9.DD.05 | Ferro-papikeite | NaFe2+2(Fe2+3Al2)(Si5Al3O22)(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 Ferro-gedrite
mindat.org URL:
https://www.mindat.org/min-1515.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Ferro-gedrite
Reference List:
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
Localities for Ferro-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.
Czech Republic | |
| Schreyer et al. (ferrocordierite) |
| Staněk | |
Finland | |
| Probed |
Germany | |
| Baumgärtl (2014) |
| Wittern (2001) |
| Wittern (2001) |
Greenland | |
| Petersen et al. (1993) |
India | |
| Mineralogical Magazine (1967) |
Japan | |
| the IMA 2012 recommendations. Comput. ... +3 other references |
| Seki et al. (1957) |
Norway | |
| Terje Karstensen collection (pers.info. to Knut Edvard Larsen 16.10.2014) +1 other reference |
Russia | |
| Barkov et al. (2021) |
USA | |
| Smith (2005) |
| John H. Betts (2009) |
| William S. Cordua collection |
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Lovejoy Gravel pits, Conway, Carroll County, New Hampshire, USA