Fetiasite
A valid IMA mineral species
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About Fetiasite
Formula:
(Fe3+,Fe2+,Ti)3(As2O5)O2
Colour:
Brown to black
Lustre:
Metallic, Sub-Metallic
Hardness:
5
Specific Gravity:
4.6
Crystal System:
Monoclinic
Name:
The name reflects its chemical composition: Iron (Fe), Titanium (Ti) and Arsenic (As).
This page provides mineralogical data about Fetiasite.
Unique Identifiers
Mindat ID:
1542
Long-form identifier:
mindat:1:1:1542:0
IMA Classification of Fetiasite
Approved
IMA Formula:
(Fe2+,Fe3+,Ti4+)3O2As3+2O5
Approval year:
1991
First published:
1994
Classification of Fetiasite
4.JB.05
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
B : Arsenites, antimonites, bismuthites; with additional anions, without H2O
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
B : Arsenites, antimonites, bismuthites; with additional anions, without H2O
45.1.13.1
45 : ACID AND NORMAL ANTIMONITES AND ARSENITES
1 : Miscellaneous
45 : ACID AND NORMAL ANTIMONITES AND ARSENITES
1 : Miscellaneous
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 |
|---|---|---|
| Fet | 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 Fetiasite
Metallic, Sub-Metallic
Transparency:
Opaque
Colour:
Brown to black
Comment:
red-brown when altered;
Streak:
Light brown to ochre
Hardness:
5 on Mohs scale
Hardness:
VHN50=440 - 490 kg/mm2 - Vickers
Hardness Data:
Measured
Cleavage:
Perfect
On {100}
On {100}
Fracture:
Irregular/Uneven, Conchoidal
Density:
4.6 g/cm3 (Measured) 4.77(3) g/cm3 (Calculated)
Optical Data of Fetiasite
Anisotropism:
Visible along grain boundaries
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 470nm | 15.4% | 16.0% |
| 546nm | 15.3% | 15.8% |
| 589nm | 14.8% | 15.2% |
| 650nm | 14.2% | 15.0% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 16.0%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Creamy white
Chemistry of Fetiasite
Mindat Formula:
(Fe3+,Fe2+,Ti)3(As2O5)O2
Element Weights:
Elements listed:
Common Impurities:
Mn
Crystallography of Fetiasite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P21/m
Cell Parameters:
a = 10.61 Å, b = 3.25 Å, c = 8.94 Å
β = 108.95°
β = 108.95°
Ratio:
a:b:c = 3.265 : 1 : 2.751
Unit Cell V:
291.57 ų (Calculated from Unit Cell)
Z:
2
Morphology:
a {100}, c {001}, m {01l}.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0001676 | Fetiasite | Graeser S, Schwander H, Demartin F, Gramaccioli C M, Pilati T, Reusser E (1994) Fetiasite (Fe2+,Fe3+,Ti)3O2[As2O5], a new arsenite mineral: Its description and structure determination American Mineralogist 79 996-1002 |  | 1994 | Cervandone | 0 | 293 |
| 0001675 | Fetiasite | Graeser S, Schwander H, Demartin F, Gramaccioli C M, Pilati T, Reusser E (1994) Fetiasite (Fe2+,Fe3+,Ti)3O2[As2O5], a new arsenite mineral: Its description and structure determination American Mineralogist 79 996-1002 | | 1994 | Lengenbach quarry, Binnatal, Switzerland | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.749 Å | (100) |
| 2.811 Å | (94) |
| 2.391 Å | (85) |
| 2.985 Å | (67) |
| 1.779 Å | (48) |
| 1.709 Å | (35) |
| 1.754 Å | (32) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 46 : Near-surface hydrothermal alteration of minerals (see also #22) |
Type Occurrence of Fetiasite
Co-Type Localities:
General Appearance of Type Material:
Crystals are covered by a thin brown-red alteration layer that renders the mineral difficult to recognize. Minute tabular crystals about 0.2 mm in diameter, forming globular aggregates of pine-cone shape, rarely exceeding 2 mm. Radial aggregates (up to 40
Place of Conservation of Type Material:
1) Department of Mineralogy, Natural History Museum, Basel, Switzerland.
2) The Mineralogical Institute, University of Basel, Switzerland.
2) The Mineralogical Institute, University of Basel, Switzerland.
Geological Setting of Type Material:
Formed from As-bearing solutions remobilized from pre-Alpine ore concentrations by Alpine metamorphism.
Associated Minerals at Type Locality:
Synonyms of Fetiasite
Other Language Names for Fetiasite
Common Associates
Associations Based on Photo Data:
| 3 photos of Fetiasite associated with Quartz | SiO2 |
| 3 photos of Fetiasite associated with Graeserite | Fe3+4Ti3As3+O13(OH) |
| 2 photos of Fetiasite associated with 'Adularia' | KAlSi3O8 |
| 1 photo of Fetiasite associated with Chamosite | Fe2+5Al(AlSi3O10)(OH)8 |
Related Minerals - Strunz-mindat Grouping
| 4.JB. | Cuyaite | Ca2Mn3+As3+14O24Cl |
| 4.JB. | Brattforsite | Mn19(AsO 3)12Cl2 |
| 4.JB.10 | Manganarsite | Mn3(As2O4)(OH)4 |
| 4.JB.15 | 'UM1984-09-AsO:ClHMn' | Mn10As6O18(OH)Cl |
| 4.JB.15 | Magnussonite | Mn2+10(As3+O3)6(OH,Cl)2 |
| 4.JB.20 | Armangite | Mn2+26(AsO3)14(HAsO3)4(CO3) |
| 4.JB.25 | Nanlingite | Na(Ca5Li)Mg12(AsO3)2[Fe(AsO3)6]F14 |
| 4.JB.30 | Asbecasite | Ca3(Ti,Sn4+)Be2(AsO3)6(SiO4)2 |
| 4.JB.35 | Stenhuggarite | CaFeSb(AsO3)2O |
| 4.JB.40 | Trigonite | Pb3Mn2+(AsO3)2(HAsO3) |
| 4.JB.45 | Finnemanite | Pb5(AsO3)3Cl |
| 4.JB.50 | Gebhardite | Pb8(As2O5)2OCl6 |
| 4.JB.55 | Graeserite | Fe3+4Ti3As3+O13(OH) |
| 4.JB.55 | Tomichite | (V,Fe)4Ti3AsO13(OH) |
| 4.JB.55 | Derbylite | Fe3+4Ti3Sb3+O13(OH) |
| 4.JB.60 | Hemloite | (Ti,V3+,Fe3+,Al)12(As3+,Sb3+)2O23(OH) |
| 4.JB.65 | Freedite | Cu+Pb8(AsO3)2O3Cl5 |
| 4.JB.70 | Georgiadesite | Pb4(As3+O3)Cl4(OH) |
| 4.JB.75 | Szklaryite | ◻Al6BAs3+3O15 |
| 4.JB.75 | Ekatite | (Fe3+,Fe2+,Zn)12(AsO3)6(AsO3,HSiO4)2(OH)6 |
| 4.JB.85 | Lepageite | Mn2+3(Fe3+7Fe2+4)O3[Sb3+5As3+8O34] |
| 4.JB.90 | Bianchiniite | Ba2(TiV)(As2O5)2OF |
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 Fetiasite
mindat.org URL:
https://www.mindat.org/min-1542.html
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References for Fetiasite
Localities for Fetiasite
Showing 4 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 | |
| McKinnon |
Italy (TL) | |
| Graeser et al. (1994) +1 other reference |
Switzerland (TL) | |
| Graeser et al. (1994) +1 other reference |
Quick NavTopAbout FetiasiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Gorb, Lärchultini, Binn, Goms, Valais, Switzerland