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Proto-ferro-anthophyllite
A valid IMA mineral species
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About Proto-ferro-anthophyllite
Formula:
◻Fe2+2Fe2+5(Si8O22)(OH)2
The anthophyllite group are orthorhombic amphiboles in the magnesium-iron-manganese amphibole subgroup. The minerals in this root name group may have either Pnma or Pnmn (proto- prefixed name) space group symmetry. The anthophyllite group's composition is defined with A(Na+K+2Ca)<0.5 apfu and C(Al+Fe3++2Ti)<1 apfu.
Proto-ferro-anthophyllite has a Pnmn space group symmetry and is defined with Fe2+ as the dominant element both in the B and C positions.
Proto-ferro-anthophyllite has a Pnmn space group symmetry and is defined with Fe2+ as the dominant element both in the B and C positions.
Colour:
brownish yellow
Lustre:
Vitreous
Specific Gravity:
3.54 (Calculated)
Crystal System:
Orthorhombic
Member of:
This page provides mineralogical data about Proto-ferro-anthophyllite.
Unique Identifiers
Mindat ID:
7254
Long-form identifier:
mindat:1:1:7254:6
IMA Classification of Proto-ferro-anthophyllite
Approved
IMA status notes:
Redefined by the IMA
IMA Formula:
Fe2+7Si8O22(OH)2
Approval year:
1986
Approval history:
Redefined in Hawthorne et al. (2012), amphibole nomenclature report.
Type description reference:
SUENO, Shigeho, MATSUURA, Shigeru, BUNNO, Michiaki, KUROSAWA, Masanori (2002) Occurrence and crystal chemical features of protoferro-anthophyllite and protomangano-ferro-anthophyllite from Cheyenne Canyon and Cheyenne Mountain, U.S.A. and Hirukawa-mura, Suisho-yama, and Yokone-yama, Japan. Journal of Mineralogical and Petrological Sciences, 97 (4) 127-136 doi:10.2465/jmps.97.127
Classification of Proto-ferro-anthophyllite
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
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 for Standard |
|---|---|---|
| Pfath | 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 Proto-ferro-anthophyllite
Vitreous
Transparency:
Transparent
Colour:
Brownish yellow
Streak:
White
Cleavage:
Perfect
(210)
(210)
Density:
3.54 g/cm3 (Calculated)
Optical Data of Proto-ferro-anthophyllite
Type:
Biaxial (-)
RI values:
nα = 1.690 nβ = 1.710 nγ = 1.726
Max. Birefringence:
δ = 0.036
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
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 (83°) 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 (83°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Chemistry of Proto-ferro-anthophyllite
Mindat Formula:
◻Fe2+2Fe2+5(Si8O22)(OH)2
The anthophyllite group are orthorhombic amphiboles in the magnesium-iron-manganese amphibole subgroup. The minerals in this root name group may have either Pnma or Pnmn (proto- prefixed name) space group symmetry. The anthophyllite group's composition is defined with A(Na+K+2Ca)<0.5 apfu and C(Al+Fe3++2Ti)<1 apfu.
Proto-ferro-anthophyllite has a Pnmn space group symmetry and is defined with Fe2+ as the dominant element both in the B and C positions.
The anthophyllite group are orthorhombic amphiboles in the magnesium-iron-manganese amphibole subgroup. The minerals in this root name group may have either Pnma or Pnmn (proto- prefixed name) space group symmetry. The anthophyllite group's composition is defined with A(Na+K+2Ca)<0.5 apfu and C(Al+Fe3++2Ti)<1 apfu.
Proto-ferro-anthophyllite has a Pnmn space group symmetry and is defined with Fe2+ as the dominant element both in the B and C positions.
Element Weights:
Elements listed:
Crystallography of Proto-ferro-anthophyllite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 9.388(2) Å, b = 18.387(4) Å, c = 5.347(1) Å
Ratio:
a:b:c = 0.511 : 1 : 0.291
Unit Cell V:
922.98 ų (Calculated from Unit Cell)
Z:
2
Comment:
Pnmn
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 |
|---|---|
| 8.353 Å | (100) |
| 3.669 Å | (20) |
| 3.277 Å | (33) |
| 3.074 Å | (64) |
| 2.560 Å | (92) |
| 2.537 Å | (24) |
| 2.317 Å | (31) |
| 1.535 Å | (31) |
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) | |
| Stage 4a: Earth’s earliest continental crust | >4.4-3.0 |
| 19 : Granitic intrusive rocks |
Type Occurrence of Proto-ferro-anthophyllite
Co-Type Localities:
General Appearance of Type Material:
acicular
Geological Setting of Type Material:
fayalite masses in granitic pegmatites
Associated Minerals at Type Locality:
Reference:
SUENO, Shigeho, MATSUURA, Shigeru, BUNNO, Michiaki, KUROSAWA, Masanori (2002) Occurrence and crystal chemical features of protoferro-anthophyllite and protomangano-ferro-anthophyllite from Cheyenne Canyon and Cheyenne Mountain, U.S.A. and Hirukawa-mura, Suisho-yama, and Yokone-yama, Japan. Journal of Mineralogical and Petrological Sciences, 97 (4) 127-136 doi:10.2465/jmps.97.127
Synonyms of Proto-ferro-anthophyllite
Other Language Names for Proto-ferro-anthophyllite
Relationship of Proto-ferro-anthophyllite to other Species
Member of:
Other Members of Anthophyllite Root Name Group:
| Anthophyllite | ◻Mg2Mg5(Si8O22)(OH)2 | Orth. mmm(2/m2/m2/m) : Pnma |
| Ferro-anthophyllite | ◻Fe2+2Fe2+5(Si8O22)(OH)2 | Orth. mmm(2/m2/m2/m) : Pnma |
| Proto-anthophyllite | ◻Mg2Mg5(Si8O22)(OH)2 | Orth. mmm(2/m2/m2/m) : Pnnm |
| 'Sodic-ferro-anthophyllite' | NaFe2+2Fe2+5(AlSi7O22)(OH)2 | Orth. |
Related Minerals - Strunz-mindat Grouping
| 9.DD.05 | Suenoite | ◻Mn2+2Mg5Si8O22(OH)2 |
| 9.DD.05 | Proto-ferro-suenoite | ◻Mn2+2(Fe2+5)(Si8O22)(OH)2 |
| 9.DD.05 | Papikeite | NaMg2(Mg3Al2}(Al3Si5O22)(OH)2 |
| 9.DD.05 | Gedrite | ◻Mg2(Mg3Al2)(Al2Si6O22)(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' | NaFe2+2Fe2+5(AlSi7O22)(OH)2 |
| 9.DD.05 | Ferro-papikeite | NaFe2+2(Fe2+3Al2)(Si5Al3O22)(OH)2 |
| 9.DD.05 | Ferro-anthophyllite | ◻Fe2+2Fe2+5(Si8O22)(OH)2 |
| 9.DD.05 | Proto-anthophyllite | ◻Mg2Mg5(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 | ◻Mg2Mg5(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.
Internet Links for Proto-ferro-anthophyllite
mindat.org URL:
https://www.mindat.org/min-7254.html
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Please feel free to link to this page.
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References for Proto-ferro-anthophyllite
Reference List:
SUENO, Shigeho, MATSUURA, Shigeru, BUNNO, Michiaki, KUROSAWA, Masanori (2002) Occurrence and crystal chemical features of protoferro-anthophyllite and protomangano-ferro-anthophyllite from Cheyenne Canyon and Cheyenne Mountain, U.S.A. and Hirukawa-mura, Suisho-yama, and Yokone-yama, Japan. Journal of Mineralogical and Petrological Sciences, 97 (4) 127-136 doi:10.2465/jmps.97.127
Localities for Proto-ferro-anthophyllite
Showing 3 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.
Japan | |
| Phys.Chem.Min. (1998) +3 other references |
| J. Mineral. Petrol. Sci. |
USA (TL) | |
| Am.Min.: 84: 196 +1 other reference |
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Hirukawa, Nakatsugawa City, Gifu Prefecture, Japan