Akatoreite
A valid IMA mineral species
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About Akatoreite
Formula:
Mn2+9Al2Si8O24(OH)8
Colour:
Yellow-orange to orange-brown
Lustre:
Vitreous
Hardness:
6
Specific Gravity:
3.48
Crystal System:
Triclinic
Name:
Named after its discovery locality at Akatore in New Zealand.
Type Locality:
Unique Identifiers
IMA Classification of Akatoreite
Approved
Approval year:
1969
Classification of Akatoreite
9.BH.15
9 : SILICATES (Germanates)
B : Sorosilicates
H : Sorosilicates with Si3O10, Si4O11, etc. anions; cations in tetrahedral [4] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
H : Sorosilicates with Si3O10, Si4O11, etc. anions; cations in tetrahedral [4] and greater coordination
57.2.3.1
57 : SOROSILICATES Si3O10 Groups and Larger Noncyclic Groups
2 : Insular Si3O10 and Larger Noncyclic Groups with [Si4O13] groups
57 : SOROSILICATES Si3O10 Groups and Larger Noncyclic Groups
2 : Insular Si3O10 and Larger Noncyclic Groups with [Si4O13] groups
16.16.8
16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
16 : Silicates Containing Aluminum and other Metals
16 : Aluminosilicates of Mn
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 |
---|---|---|
Akt | 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 Akatoreite
Vitreous
Transparency:
Transparent
Colour:
Yellow-orange to orange-brown
Streak:
yellowish white
Hardness:
6 on Mohs scale
Cleavage:
Perfect
Good on {010} , poor on {012}
Good on {010} , poor on {012}
Density:
3.48 g/cm3 (Measured) 3.47 g/cm3 (Calculated)
Optical Data of Akatoreite
Type:
Biaxial (+)
RI values:
nα = 1.698 nβ = 1.704 nγ = 1.720
2V:
Measured: 65° , Calculated: 64°
Max Birefringence:
δ = 0.022
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
High
Dispersion:
relatively strong
Pleochroism:
Visible
Comments:
X = colorless; Y = pale yellow; Z = light canary-yellow
Chemistry of Akatoreite
Mindat Formula:
Mn2+9Al2Si8O24(OH)8
Common Impurities:
Ti,Fe,Mg,Ca
Crystallography of Akatoreite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 8.337(2) Å, b = 10.367(2) Å, c = 7.629(1) Å
α = 104.46(1)°, β = 93.81(2)°, γ = 104.18(1)°
α = 104.46(1)°, β = 93.81(2)°, γ = 104.18(1)°
Ratio:
a:b:c = 0.804 : 1 : 0.736
Unit Cell V:
613.28 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Rarely as sheaves, to 1 cm, of radiating prisms, elongated and striated parallel[100] ; fibrous, fine granular, massive.
Twinning:
Twinning: On {021} twin axis perpindicular
{021}, lamellar in thin section.
{021}, lamellar in thin section.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
---|---|---|---|---|---|---|---|
0005298 | Akatoreite | Burns P C, Hawthorne F C (1993) Edge-sharing MnO4 tetrahedra in the structure of akatoreite, Mn9Al2Si8O24(OH)8 The Canadian Mineralogist 31 321-329 | 1993 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
4.665 Å | (100) |
3.310 Å | (90) |
2.214 Å | (80) |
9.681 Å | (60) |
3.466 Å | (50) |
3.063 Å | (50) |
2.866 Å | (50) |
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) | |
High-𝑇 alteration and/or metamorphism | |
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Geological Setting:
in manganiferous potassium-rich felsic metavolcanics (Norberg, Sweden).
Type Occurrence of Akatoreite
General Appearance of Type Material:
Rarely as sheaves, to 1 cm, of radiating prisms; fibrous granular, massive.
Place of Conservation of Type Material:
University of Otago, Dunedin; Geological Survey of New Zealand, Lower Hutt, New Zealand; National Museum of Natural History, Washington, D.C., USA, 137285, 142541.
Geological Setting of Type Material:
In a manganiferous metachert and carbonate lens in schists
Associated Minerals at Type Locality:
Reference:
Read, P.B., Reay, A. (1971) Akatoreite, a new manganese silicate from eastern Otago, New Zealand. American Mineralogist; 56: 416-426.
Synonyms of Akatoreite
Other Language Names for Akatoreite
Common Associates
Associated Minerals Based on Photo Data:
3 photos of Akatoreite associated with Rhodonite | CaMn3Mn[Si5O15] |
2 photos of Akatoreite associated with Rhodochrosite | MnCO3 |
1 photo of Akatoreite associated with Alabandite | MnS |
1 photo of Akatoreite associated with Pyrolusite | Mn4+O2 |
1 photo of Akatoreite associated with Piemontite | (CaCa)(AlAlMn3+)O[Si2O7][SiO4](OH) |
1 photo of Akatoreite associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
9.BH. | Bunnoite | Mn2+6AlSi6O18(OH)3 |
9.BH.05 | Aminoffite | Ca2(Be,Al)(Si2O7)(H2O,OH) |
9.BH.10 | Kinoite | Ca2Cu2(H2O)2[Si3O10] |
9.BH.20 | Fencooperite | Ba6Fe3+3Si8O23(CO3)2Cl3 · H2O |
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 Akatoreite
mindat.org URL:
https://www.mindat.org/min-68.html
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References for Akatoreite
Localities for Akatoreite
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).
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.
All localities listed without proper references should be considered as questionable.
Austria | |
| Kolitsch et al. (2019) |
Italy | |
| Piccoli et al. (2007) +1 other reference |
Japan | |
| The Mineral Species of Japan (5th ed) +1 other reference |
New Zealand (TL) | |
| Read et al. (1971) +1 other reference |
Sweden | |
| Ounchanum et al. (1987) |
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Maniglia Mt. Mine, Bellino, Cuneo Province, Piedmont, Italy