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Arakiite
A valid IMA mineral species
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About Arakiite
Formula:
(Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23
Colour:
Red-brown to orange-brown
Lustre:
Earthy
Hardness:
3 - 4
Specific Gravity:
3.41 (Calculated)
Crystal System:
Monoclinic
Member of:
Name:
Named in honor of Dr. Takaharu Araki [December 22, 1929 Kyoto, Japan - September 07, 2004 Lynwood, Washington, USA], professor at University of Chicago and later translator for Chemical Abstracts, for his numerous mineral crystal-structure determinations and contributions to the science of mineralogy.
This page provides mineralogical data about Arakiite.
Unique Identifiers
Mindat ID:
6805
Long-form identifier:
mindat:1:1:6805:1
Similar Names
IMA Classification of Arakiite
Approved
IMA Formula:
Zn2+Mn2+12Fe3+2(As3+O3)(As5+O4)2(OH)23
Approval year:
1998
First published:
2000
Classification of Arakiite
8.BE.45
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ark | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Arakiite
Earthy
Transparency:
Translucent, Opaque
Colour:
Red-brown to orange-brown
Streak:
Pale-brown, red-brown
Hardness:
3 - 4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {001}.
Perfect on {001}.
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
3.41 g/cm3 (Calculated)
Optical Data of Arakiite
Type:
Biaxial (-)
RI values:
nα = 1.723 nβ = 1.744 nγ = 1.750
2V:
Measured: 40° to 44°, Calculated: 54°
Birefringence:
0.027
Max. Birefringence:
δ = 0.027
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 Âĩm 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 Âĩm 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.
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.
Dispersion:
r > v medium
Pleochroism:
Not Visible
Chemistry of Arakiite
Mindat Formula:
(Zn,Mn2+)(Mn2+,Mg)12(Fe3+,Al)2(As5+O4)2(As3+O3)(OH)23
Element Weights:
Crystallography of Arakiite
Crystal System:
Monoclinic
Class (H-M):
m - Domatic
Space Group:
Bb
Setting:
Cc
Cell Parameters:
a = 14.248(8) Å, b = 8.228(4) Å, c = 24.23(1) Å
β = 93.62(3)°
β = 93.62(3)°
Ratio:
a:b:c = 1.732 : 1 : 2.945
Unit Cell V:
2843 Ã
Âģ
Z:
4
Morphology:
Predominantly anhedral, mica-like.
Twinning:
None observed
Crystal Structure
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Unit Cell | Unit Cell Packed
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) |
|---|---|---|---|---|---|---|---|
| 0005637 | Arakiite | Cooper M A, Hawthorne F C (1999) The effect of differences in coordination on ordering of polyvalent cations in close-packed structures: The crystal structure of arakiite and comparison with hematolite The Canadian Mineralogist 37 1471-1482 |  | 1999 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.07 Ã | (100) |
| 6.046 Ã | (100) |
| 5.463 Ã | (10) |
| 5.262 Ã | (20) |
| 4.764 Ã | (15) |
| 4.119 Ã | (30) |
| 4.040 Ã | (90) |
| 3.952 Ã | (10) |
| 3.822 Ã | (5) |
| 3.648 Ã | (10) |
| 3.572 Ã | (5) |
| 3.496 Ã | (5) |
| 3.404 Ã | (20) |
| 3.317 Ã | (5) |
| 3.223 Ã | (10) |
| 3.148 Ã | (30) |
| 3.030 Ã | (70) |
| 2.862 Ã | (5b) |
| 2.799 Ã | (5) |
| 2.749 Ã | (5) |
| 2.700 Ã | (10) |
| 2.631 Ã | (20) |
| 2.594 Ã | (5) |
| 2.546 Ã | (5) |
| 2.498 Ã | (20) |
| 2.411 Ã | (40) |
| 2.372 Ã | (15) |
| 2.338 Ã | (15) |
| 2.291 Ã | (10b) |
| 2.237 Ã | (5b) |
| 2.157 Ã | (5b) |
| 2.106 Ã | (5) |
| 2.065 Ã | (20b) |
| 2.017 Ã | (10) |
| 1.905 Ã | (5) |
| 1.859 Ã | (20) |
| 1.810 Ã | (15) |
| 1.777 Ã | (5) |
| 1.748 Ã | (20) |
| 1.661 Ã | (5) |
| 1.619 Ã | (5) |
| 1.573 Ã | (20) |
| 1.552 Ã | (70) |
Comments:
Roberts, A., et al. (2000) A New Zn-bearing Hematolite-like Mineral from Varmland, Sweden, Mineralogical Record, v. 30, p. 253-256. Note: Arakiite is very similar to the "Hematolite-like" Group.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Arakiite
General Appearance of Type Material:
Thin foliated reddish-colored masses on ore-bearing matrix. Megascopically indistinguishable from dixenite and hematolite.
Place of Conservation of Type Material:
Harvard Mineralogical Museum, Cambridge, Massachusetts, cat. no. 134608.
The Natural History Museum, London, UK, BM1921.310. (additional material)
The Natural History Museum, London, UK, BM1921.310. (additional material)
Chemical Analysis of Type Material:
| ZnO | 4.48 % |
|---|---|
| MnO | 34.32 % |
| MgO | 12.76 % |
| Fe2O3 | 6.76 % |
| Al2O3 | 2.25 % |
| As2O3 | 6.56 % |
| As2O5 | 15.84 % |
| H2O (calc) | 13.74 % |
| Total: | 96.71 % |
Associated Minerals at Type Locality:
Synonyms of Arakiite
Other Language Names for Arakiite
Relationship of Arakiite to other Species
Member of:
Other Members of Hematolite Group:
| Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 | Trig. 3 : R3 |
| Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 | Trig. 3 : R3 |
| Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 | Orth. 222 : C2221 |
| Mcgovernite | Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21 | Trig. 3m : R3c |
| Synadelphite | Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O | Orth. mmm(2/m2/m2/m) : Pnma |
| Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x | Trig. |
Common Associates
Associations Based on Photo Data:
| 2 photos of Arakiite associated with Rhodochrosite | MnCO3 |
Related Minerals - Strunz-mindat Grouping
| 8.BE.05 | Augelite | Al2(PO4)(OH)3 |
| 8.BE.10 | Grattarolaite | Fe3+3(PO4)O3 |
| 8.BE.15 | Cornetite | Cu3(PO4)(OH)3 |
| 8.BE.20 | Clinoclase | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Gilmarite | Cu3(AsO4)(OH)3 |
| 8.BE.25 | Arhbarite | Cu2Mg(AsO4)(OH)3 |
| 8.BE.30 | Flinkite | Mn2+2Mn3+(AsO4)(OH)4 |
| 8.BE.30 | Argandite | Mn7(VO4)2(OH)8 |
| 8.BE.30 | Raadeite | Mg7(PO4)2(OH)8 |
| 8.BE.30 | Allactite | Mn2+7(AsO4)2(OH)8 |
| 8.BE.35 | 'Mineral E (of Dunn, et. al., 1982)' | |
| 8.BE.35 | Chlorophoenicite | (Mn,Mg)3Zn2(AsO4)(OH,O)6 |
| 8.BE.35 | Magnesiochlorophoenicite | (Mg,Mn)3Zn2(AsO4)(OH,O)6 |
| 8.BE.40 | Gerdtremmelite | (Zn,Fe)(Al,Fe)2(AsO4)(OH)5 |
| 8.BE.45 | Dixenite | CuMn2+14Fe2+(SiO4)2(As5+O4)(As3+O3)5(OH)6 |
| 8.BE.45 | Mcgovernite | Mn19Zn3(AsO4)3(AsO3)(SiO4)3(OH)21 |
| 8.BE.45 | Hematolite | (Mn,Mg,Al,Fe3+)15(As5+O4)2(As3+O3)(OH)23 |
| 8.BE.45 | Turtmannite | (Mn,Mg)22.5Mg3-3x((V5+,As5+)O4)3(As3+O3)x(SiO4)3O5-5x(OH)20+x |
| 8.BE.45 | Carlfrancisite | Mn2+3(Mn2+,Mg,Fe3+,Al)42[As3+O3]2(As5+O4)4[(Si,As5+)O4]6[(As5+,Si)O4]2(OH)42 |
| 8.BE.45 | Kraisslite | Zn3(Mn,Mg)25(Fe3+,Al)(As3+O3)2[(Si,As5+)O4]10(OH)16 |
| 8.BE.50 | Synadelphite | Mn2+9(As5+O4)2(As3+O3)(OH)9 · 2H2O |
| 8.BE.55 | Holdenite | (Mn2+,Mg)6Zn3(AsO4)2(SiO4)(OH)8 |
| 8.BE.60 | Kolicite | Mn2+7Zn4(AsO4)2(SiO4)2(OH)8 |
| 8.BE.65 | Sabelliite | (Cu,Zn)2Zn(AsO4,SbO4)(OH)3 |
| 8.BE.70 | Jarosewichite | Mn2+3Mn3+(AsO4)(OH)6 |
| 8.BE.75 | Theisite | Cu5Zn5(AsO4,SbO4)2(OH)14 |
| 8.BE.80 | Coparsite | Cu4(AsO4,VO4)O2Cl |
| 8.BE.85 | Waterhouseite | Mn2+7(PO4)2(OH)8 |
| 8.BE.90 | Vasilseverginite | Cu9O4(AsO4)2(SO4)2 |
Fluorescence of Arakiite
No fluorescence under SW or LW UV.
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 Arakiite
mindat.org URL:
https://www.mindat.org/min-6805.html
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References for Arakiite
Localities for Arakiite
Showing 6 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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.
Sweden (TL) | |
| Roberts et al. (2000) |
| Thulin et al. (2007) | |
| RRUFF ID: R060812 +1 other reference | |
| The Swedish Museum of Natural History ... | |
USA | |
| Hexiong Yang |
| Hexiong Yang |
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Franklin Mine, Franklin, Sussex County, New Jersey, USA