Fetiasite

A valid IMA mineral species

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Fetiasite

Gorb, Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Gorb, Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Gorb, Lärchultini, Binn, Goms, Valais, Switzerland

Fetiasite

Lärchultini, Binn, Goms, Valais, Switzerland

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About FetiasiteHide

Formula:

(Fe³⁺,Fe²⁺,Ti)₃(As₂O₅)O₂

Colour:

Brown to black

Lustre:

Metallic, Sub-Metallic

Hardness:

Specific Gravity:

4.6

Crystal System:

Monoclinic

Name:

The name reflects its chemical composition: Iron (Fe), Titanium (Ti) and Arsenic (As).

Co-Type Localities:

ⓘ Monte Cervandone area, Devero Alp, Baceno, Verbano-Cusio-Ossola Province, Piedmont, Italy
ⓘ Gorb, Lärchultini, Binn, Goms, Valais, Switzerland

This page provides mineralogical data about Fetiasite.

Unique IdentifiersHide

Mindat ID:

1542

Long-form identifier:

mindat:1:1:1542:0

IMA Classification of FetiasiteHide

IMA status:

Approved

IMA Formula:

(Fe²⁺,Fe³⁺,Ti⁴⁺)₃O₂As³⁺₂O₅

Approval year:

1991

First published:

1994

Type description reference:

Graeser, Stefan, Schwander, Hans, Demartin, Francesco, Gramaccioli, Carlo M., Pilati, Tullio, Reusser, Eric (1994) Fetiasite (Fe2+,Fe3+,Ti)3O2[As2O5], a new arsenite mineral: Its description and structure determination. American Mineralogist, 79 (9-10) 996-1002

Classification of FetiasiteHide

Strunz-mindat (2026):

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

Dana 8th ed.:

45.1.13.1

45 : ACID AND NORMAL ANTIMONITES AND ARSENITES
1 : Miscellaneous

Mineral SymbolsHide

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 FetiasiteHide

Lustre:

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}

Fracture:

Irregular/Uneven, Conchoidal

Density:

4.6 g/cm³ (Measured) 4.77(3) g/cm³ (Calculated)

Optical Data of FetiasiteHide

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 FetiasiteHide

Mindat Formula:

(Fe³⁺,Fe²⁺,Ti)₃(As₂O₅)O₂

Element Weights:

Element	% weight
Fe	39.018 %
As	34.898 %
O	26.084 %

Calculated from ideal end-member formula.

Elements listed:

As, Fe, O, Ti - search for minerals with similar chemistry

Common Impurities:

Crystallography of FetiasiteHide

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°

Ratio:

a:b:c = 3.265 : 1 : 2.751

Unit Cell V:

291.57 Å³ (Calculated from Unit Cell)

Morphology:

a {100}, c {001}, m {01l}.

Crystal StructureHide

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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

data_global
_chemical_name_mineral 'Fetiasite'
loop_
_publ_author_name
'Graeser S'
'Schwander H'
'Demartin F'
'Gramaccioli C M'
'Pilati T'
'Reusser E'
_journal_name_full 'American Mineralogist'
_journal_volume 79 
_journal_year 1994
_journal_page_first 996
_journal_page_last 1002
_publ_section_title
;
 Fetiasite (Fe2+,Fe3+,Ti)3O2[As2O5], a new arsenite mineral: Its description
 and structure determination
 Note: Sample A
;
_database_code_amcsd 0001676
_chemical_compound_source 'Cervandone'
_chemical_formula_sum 'As2 Fe2.38 Ti.54 O7'
_cell_length_a 10.614
_cell_length_b 3.252
_cell_length_c 8.945
_cell_angle_alpha 90
_cell_angle_beta 108.95
_cell_angle_gamma 90
_cell_volume 292.018
_exptl_crystal_density_diffrn      4.784
_symmetry_space_group_name_H-M 'P 1 21/m 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  'x,1/2-y,z'
  '-x,1/2+y,-z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
As1   0.40970   0.25000   0.66474   1.00000
As2   0.24978   0.25000   0.24797   1.00000
Fe1   0.04922   0.25000   0.86648   1.00000
Fe2   0.64241   0.25000   0.02199   1.00000
Fe   0.88301   0.25000   0.39371   0.38000
Ti   0.88301   0.25000   0.39371   0.54000
O1   0.08150   0.25000   0.11560   1.00000
O2   0.32920   0.25000   0.10350   1.00000
O3   0.83220   0.25000   0.15810   1.00000
O4   0.99300   0.25000   0.61930   1.00000
O5   0.43320   0.25000   0.87260   1.00000
O6   0.23480   0.25000   0.59930   1.00000
O7   0.72790   0.25000   0.67690   0.50000
O8   0.55200   0.25000   0.38270   0.50000
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
As1 0.00880 0.00950 0.00880 0.00000 0.00270 0.00000
As2 0.00930 0.01000 0.01040 0.00000 0.00320 0.00000
Fe1 0.01130 0.01020 0.01230 0.00000 0.00390 0.00000
Fe2 0.00720 0.00840 0.00960 0.00000 0.00210 0.00000
Fe 0.01740 0.01590 0.01160 0.00000 0.00160 0.00000
Ti 0.01740 0.01590 0.01160 0.00000 0.00160 0.00000
O1 0.00800 0.02400 0.01800 0.00000 0.00000 0.00000
O2 0.02000 0.02300 0.01700 0.00000 0.01000 0.00000
O3 0.00900 0.02200 0.00900 0.00000 0.00000 0.00000
O4 0.01000 0.04700 0.00900 0.00000 0.00160 0.00000
O5 0.01200 0.02700 0.00900 0.00000 0.00310 0.00000
O6 0.01300 0.09100 0.01400 0.00000 0.00200 0.00000
O7 0.02300 0.01200 0.01700 0.00000 0.00500 0.00000
O8 0.03300 0.02600 0.02000 0.00000 0.00800 0.00000

X-Ray Powder DiffractionHide

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 EnvironmentHide

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 FetiasiteHide

Co-Type Localities:

ⓘ Monte Cervandone area, Devero Alp, Baceno, Verbano-Cusio-Ossola Province, Piedmont, Italy
ⓘ Gorb, Lärchultini, Binn, Goms, Valais, Switzerland

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.

Geological Setting of Type Material:

Formed from As-bearing solutions remobilized from pre-Alpine ore concentrations by Alpine metamorphism.

Associated Minerals at Type Locality:

Anatase	Asbecasite	Cafarsite	Cervandonite-(Ce)	Chlorite Group
Quartz

Reference:

Synonyms of FetiasiteHide

IMA1991-019

Other Language Names for FetiasiteHide

Dutch:Fetiasiet

German:Fetiasit

Russian:Фетиасит

Spanish:Fetiasita

Common AssociatesHide

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 Hide

4.JB.	Cuyaite	Ca₂Mn³⁺As³⁺₁₄O₂₄Cl	Mon. m
4.JB.	Brattforsite	Mn₁₉(AsO ₃)₁₂Cl₂	Mon. 2/m : B2/b
4.JB.10	Manganarsite	Mn₃(As₂O₄)(OH)₄	Trig.
4.JB.15	'UM1984-09-AsO:ClHMn'	Mn₁₀As₆O₁₈(OH)Cl	Tet. 4/mmm(4/m2/m2/m) : I4₁/acd
4.JB.15	Magnussonite	Mn²⁺₁₀(As³⁺O₃)₆(OH,Cl)₂	Iso. m3m(4/m32/m) : Ia3d
4.JB.20	Armangite	Mn²⁺₂₆(AsO₃)₁₄(HAsO₃)₄(CO₃)	Trig. 3 : P3
4.JB.25	Nanlingite	Na(Ca₅Li)Mg₁₂(AsO₃)₂[Fe(AsO₃)₆]F₁₄	Trig. 3m(32/m) : R3m
4.JB.30	Asbecasite	Ca₃(Ti,Sn⁴⁺)Be₂(AsO₃)₆(SiO₄)₂	Trig. 3m : P3c1
4.JB.35	Stenhuggarite	CaFeSb(AsO₃)₂O	Tet. 4/mmm(4/m2/m2/m) : I4₁/amd
4.JB.40	Trigonite	Pb₃Mn²⁺(AsO₃)₂(HAsO₃)	Mon. m
4.JB.45	Finnemanite	Pb₅(AsO₃)₃Cl	Hex. 6/m : P6₃/m
4.JB.50	Gebhardite	Pb₈(As₂O₅)₂OCl₆	Mon. 2/m : P2₁/c
4.JB.55	Graeserite	Fe³⁺₄Ti₃As³⁺O₁₃(OH)	Mon. 2/m : B2/m
4.JB.55	Tomichite	(V,Fe)₄Ti₃AsO₁₃(OH)	Mon. 2/m : P2₁/m
4.JB.55	Derbylite	Fe³⁺₄Ti₃Sb³⁺O₁₃(OH)	Mon. 2/m : P2₁/m
4.JB.60	Hemloite	(Ti,V³⁺,Fe³⁺,Al)₁₂(As³⁺,Sb³⁺)₂O₂₃(OH)	Tric. 1 : P1
4.JB.65	Freedite	Cu⁺Pb₈(AsO₃)₂O₃Cl₅	Mon. 2/m : B2/m
4.JB.70	Georgiadesite	Pb₄(As³⁺O₃)Cl₄(OH)	Mon. 2/m : P2₁/c
4.JB.75	Szklaryite	◻Al₆BAs³⁺₃O₁₅	Orth. mmm(2/m2/m2/m) : Pbcm
4.JB.75	Ekatite	(Fe³⁺,Fe²⁺,Zn)₁₂(AsO₃)₆(AsO₃,HSiO₄)₂(OH)₆	Hex. 6mm : P6₃mc
4.JB.85	Lepageite	Mn²⁺₃(Fe³⁺₇Fe²⁺₄)O₃[Sb³⁺₅As³⁺₈O₃₄]	Tric. 1 : P1
4.JB.90	Bianchiniite	Ba₂(TiV)(As₂O₅)₂OF	Tet. 4/mmm(4/m2/m2/m) : I4/mcm

Other InformationHide

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 FetiasiteHide

mindat.org URL:

https://www.mindat.org/min-1542.html
Please feel free to link to this page.

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External Links:

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Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for FetiasiteHide

Reference List:

Skrapits, A. (1996) Fetiasit, eine neue Mineralart im Lercheltini. Binntal (VS). Schweizer Strahler: 10(10): 380-388 (in German and French).

Mandarino, Joseph A. (1997) New Minerals 1990-1994. The Mineralogical Record Inc., Tuscon, Arizona. 220pp.

(2005) Fetiasite. Handbook of Mineralogy. Mineralogical Society of America

Roth, P. (2007) Fetiasite. in Minerals first discovered in Switzerland and minerals named after Swiss individuals, Kristallografik Verlag (Achberg Germany): 62-63.

Guastoni, A., Nestola, F., Zorzi, F. (2020) Novità dal Monte Cervandone (Val Devero, VB). I ritrovamenti di tinnunculite, rabdofane-(La), parnauite, hingganite-(Y), fetiasite. Rivista Mineralogica Italiana: 44(3): 144-156.

Localities for FetiasiteHide

Showing 4 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the

symbol to view information about a locality. The

symbol next to localities in the list can be used to jump to that position on the map.

Hide all sections | Show all sections

Locality ListHide

- 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). ~~Struck out~~ - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.


Australia
New South Wales Kennedy Co. Condobolin district Mineral Hill field ⓘ Pearse North Open Cut ?	McKinnon

Italy (TL)
Piedmont Verbano-Cusio-Ossola Province Baceno Devero Alp ⓘ Monte Cervandone area (TL)	Graeser et al. (1994) +1 other reference

Switzerland (TL)
Valais Goms Binn Lärchultini ⓘ Gorb (TL)	Graeser et al. (1994) +1 other reference
ⓘ Wanni glacier - Scherbadung area (Monte Cervandone)

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Fetiasite

About FetiasiteHide

Unique IdentifiersHide

IMA Classification of FetiasiteHide

Classification of FetiasiteHide

Mineral SymbolsHide

Physical Properties of FetiasiteHide

Optical Data of FetiasiteHide

Chemistry of FetiasiteHide

Crystallography of FetiasiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of FetiasiteHide

Synonyms of FetiasiteHide

Other Language Names for FetiasiteHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

Other InformationHide

Internet Links for FetiasiteHide

References for FetiasiteHide

Localities for FetiasiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide