Akrochordite (original) (raw)

A valid IMA mineral species - grandfathered

About AkrochorditeHide

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Formula:

MnMn2Mn2(AsO4)2(OH)4(H2O)4

Simplified: (Mn2+)5(AsO4)2(OH)4 · 4H2O.
Type material contains some Mg replacing Mn.

Colour:

Yellowish red-brown, pale to dark brown, pale pink,

Lustre:

Sub-Vitreous, Resinous, Dull

Specific Gravity:

3.194 - 3.35

Crystal System:

Monoclinic

Name:

Named by Gustav Flink in 1922 from Greek ακρόχορδον (akrochordon) = "a wart," in allusion to the appearance of its form of aggregation.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:72:3

5f250b01-9289-4e5b-9d33-762bd3487422

IMA Classification of AkrochorditeHide

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Approved, 'Grandfathered' (first described prior to 1959)

Type description reference:

Classification of AkrochorditeHide

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8.DD.10

8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
D : With only medium-sized cations, (OH, etc.):RO4= 2:1

42.4.1.1

42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
4 : (AB)5(XO4)2Zq·xH2O

20.8.11

20 : Arsenates (also arsenates with phosphate, but without other anions)
8 : Arsenates of Mn

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Symbol	Source	Reference
Akr	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 AkrochorditeHide

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Sub-Vitreous, Resinous, Dull

Colour:

Yellowish red-brown, pale to dark brown, pale pink,

Cleavage:

Perfect
On {010} , perfect; a second, perpendicular to the first.

Density:

3.194 - 3.35 g/cm3 (Measured) 3.26 g/cm3 (Calculated)

Optical Data of AkrochorditeHide

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RI values:

_n_α = 1.672 _n_β = 1.676 _n_γ = 1.683

δ = 0.011

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Dispersion:

r < v relatively strong

Optical Extinction:

Y^c ~ 45°, X = b

Pleochroism:

Non-pleochroic

Chemistry of AkrochorditeHide

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Mindat Formula:

MnMn2Mn2(AsO4)2(OH)4(H2O)4

Simplified: (Mn2+)5(AsO4)2(OH)4 · 4H2O.
Type material contains some Mg replacing Mn.

Crystallography of AkrochorditeHide

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Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 5.682 Å, b = 17.627 Å, c = 6.832 Å
β = 99.5°

Ratio:

a:b:c = 0.322 : 1 : 0.388

Unit Cell V:

674.89 Å³ (Calculated from Unit Cell)

Morphology:

Crystals are prismatic to lathlike, elongated along [201], generally splayed or tapered, to 2 mm; may be in radial aggregates and subparallel sheaves. Typically as wartlike or spherical aggregates of minute crystals.

Crystal StructureHide

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2x2x2 |3x3x3 |4x4x4

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ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0001206	Akrochordite	Moore P B, Sen Gupta P K, Schlemper E O (1989) Akrochordite, (Mn,Mg)5(OH)4(H2O)4(AsO4)2: A sheet structure with amphibole walls American Mineralogist 74 256-262		1989	0	293

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

d-spacing	Intensity
8.79 Å	(80)
5.31 Å	(35)
4.40 Å	(100)
3.62 Å	(40)
3.112 Å	(35)
3.062 Å	(35)
2.750 Å	(50)

Geological EnvironmentHide

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Geological Setting:

in fractures in a metamorphosed zinc orebody (Sterling Hill, New Jersey, USA).

Type Occurrence of AkrochorditeHide

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General Appearance of Type Material:

Small, rounded wartlike aggregates

Place of Conservation of Type Material:

National Museum of Natural History, Washington, D.C., USA, 162614, R5396.

Chemical Analysis of Type Material:

P2O5	0.42 %
As2O5	33.51 %
MnO	38.98 %
Mn2O3	0.50 %
FeO	0.46 %
MgO	6.94 %
K2O	0.55 %
Na2O	1.18 %
CaO	0.99 %
H2O	16.78 %
Total:	100.31 %

Geological Setting of Type Material:

A rare mineral in hausmannite ore from a metamorphosed Fe–Mn orebody

Associated Minerals at Type Locality:

Reference:

Flink, G. (1922) Akrochordit, ett nytt mineral från Långbans gruvor. Geologiska Föreningens i Stockholm Förhandlinger: 44: 773-776.

Synonyms of AkrochorditeHide

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Other Language Names for AkrochorditeHide

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Relationship of Akrochordite to other SpeciesHide

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Other Members of this group:

Guanacoite	MgCu2Mg2(AsO4)2(OH)4(H2O)4	Mon. 2/m : _P_21/b

Common AssociatesHide

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Associated Minerals Based on Photo Data:

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8.DD.	Penberthycroftite	[Al6(AsO4)3(OH)9(H2O)5] · 8H2O	Mon. 2/m : _P_21/b
8.DD.	Bettertonite	[Al6(AsO4)3(OH)9(H2O)5] · 11H2O	Mon. 2/m : _P_21/b
8.DD.	Vargite	MnCu2Mn2(AsO4)2(OH)4(H2O)4	Mon. 2/m : _P_21/b
8.DD.	Galeaclolusite	Al6(AsO4)3(OH)9(H2O)4 · 8H2O	Orth. m m m _(_2/_m_2/_m_2/m ) : P n m a
8.DD.05	Luetheite	Cu2Al2(AsO4)2(OH)4	Mon. 2/m : _P_21/m
8.DD.05	Chenevixite	Cu2Fe3+2(AsO4)2(OH)4	Mon. 2/m : _P_21/m
8.DD.10	Guanacoite	MgCu2Mg2(AsO4)2(OH)4(H2O)4	Mon. 2/m : _P_21/b
8.DD.15	UM1981-32-PO:FeH	Fe2+Fe3+6(PO4)4-x[PO3(OH)]x(OH)8 · 4H2O
8.DD.15	Afmite	Al3(OH)4(H2O)3(PO4)(PO3OH) · H2O	Tric. 1 : _P_1
8.DD.15	Aheylite	(Fe2+,Zn)Al6(PO4)4(OH)8 · 4H2O	Tric. 1 : _P_1
8.DD.15	Coeruleolactite	Tric. 1 : _P_1
8.DD.15	Faustite	ZnAl6(PO4)4(OH)8 · 4H2O	Tric. 1 : _P_1
8.DD.15	Planerite	Al6(PO4)2(PO3OH)2(OH)8 · 4H2O	Tric. 1 : _P_1
8.DD.15	Chalcosiderite	CuFe3+6(PO4)4(OH)8 · 4H2O	Tric. 1 : _P_1
8.DD.15	Turquoise	CuAl6(PO4)4(OH)8 · 4H2O	Tric. 1 : _P_1
8.DD.20	Eosphorite	Mn2+Al(PO4)(OH)2 · H2O	Orth. m m m _(_2/_m_2/_m_2/m ) : C m c a
8.DD.20	Ernstite	(Mn2+,Fe3+)Al(PO4)(OH,O)2 · H2O	Mon.
8.DD.20	Lefontite	Fe2Al2Be(PO4)2(OH)6	Orth. m m m _(_2/_m_2/_m_2/m ) : C m c a
8.DD.20	Childrenite	Fe2+Al(PO4)(OH)2 · H2O	Orth. m _m_2 : C c _c_2
8.DD.25	Kobokoboite	Al6(PO4)4(OH)6 · 11H2O	Tric.
8.DD.30	Smamite	Ca2Sb(OH)4[H(AsO4)2] · 6H2O	Tric. 1 : _P_1
8.DD.35	Gutsevichite	Al3(PO4)2(OH)3 · 8H2O	Iso.
8.DD.40	Laubmannite (of Moore)	(Fe3+,Fe2+,M)8+x(OH,H2O)9(H2O)2(PO4)5, M = Fe3+, Cu2+ or other metal cation, x ~ 0.1.	Orth. m m m _(_2/_m_2/_m_2/m ) : P b c m

Fluorescence of AkrochorditeHide

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Other InformationHide

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Notes:

Readily soluble in dilute H2SO4, yielding a purple (lilac) solution.

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 AkrochorditeHide

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References for AkrochorditeHide

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Reference List:

Palache, Charles, Berman, Harry, Frondel, Clifford (1951) The System of Mineralogy (7th ed.) Vol. 2 - Halides, Nitrates, Borates, Carbonates, Sulfates, Phosphates, Arsenates, Tungstates, Molybdates, Ect. John Wiley and Sons, New York.

Gaines, Richard V., Skinner, H. Catherine W., Foord, Eugene E., Mason, Brian, Rosenzweig, Abraham, King, Vandall T. (1997) Dana's New Mineralogy (8th ed.). Wiley-Interscience. p.1872

Localities for AkrochorditeHide

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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.

Locality ListHide

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- 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.

Germany
Lower Saxony Göttingen District Bad Grund Bergstadt Bad Grund ⓘ Grund mine	Haack et al. (1987)
Sweden (TL)
Värmland County Filipstad Långban Ore District ⓘ Långban Mine (TL)	Flink (1922) +3 other references
ⓘ Japan working	Flink (1922)
Nordmark Odal Field ⓘ Moss mine	Langhof (2003)
USA
New Jersey Sussex County Ogdensburg Sterling Hill ⓘ Sterling Mine	Dunn (1981) +1 other reference

Akrochordite (original) (raw)

About AkrochorditeHide

Unique IdentifiersHide

IMA Classification of AkrochorditeHide

Classification of AkrochorditeHide

Mineral SymbolsHide

Physical Properties of AkrochorditeHide

Optical Data of AkrochorditeHide

Chemistry of AkrochorditeHide

Crystallography of AkrochorditeHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of AkrochorditeHide

Synonyms of AkrochorditeHide

Other Language Names for AkrochorditeHide

Relationship of Akrochordite to other SpeciesHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

Fluorescence of AkrochorditeHide

Other InformationHide

Internet Links for AkrochorditeHide

References for AkrochorditeHide

Localities for AkrochorditeHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide