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Aluminocopiapite
A valid IMA mineral species - grandfathered
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About Aluminocopiapite
Formula:
Al2/3Fe3+4(SO4)6(OH)2 · 20H2O
Colour:
Pale lemon-yellow to deep yellow
Lustre:
Vitreous
Hardness:
2 - 3
Specific Gravity:
2.163 (Calculated)
Crystal System:
Triclinic
Member of:
Name:
In allusion to its composition containing aluminum in substitution for ferric iron and its relationship to copiapite.
Unique Identifiers
Mindat ID:
87
Long-form identifier:
mindat:1:1:87:7
IMA Classification of Aluminocopiapite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
(Al,Mg)Fe3+4(S6+O4)6(OH,O)2·20H2O
First published:
1947
Classification of Aluminocopiapite
7.DB.35
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
B : With only medium-sized cations; insular octahedra and finite units
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
B : With only medium-sized cations; insular octahedra and finite units
Dana 7th ed.:
31.10.5.7
31.10.5.7
31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
10 : Miscellaneous
31 : HYDRATED SULFATES CONTAINING HYDROXYL OR HALOGEN
10 : Miscellaneous
25.11.25
25 : Sulphates
11 : Sulphates of Fe and other metals
25 : Sulphates
11 : Sulphates of Fe and other metals
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 |
|---|---|---|
| Acpi | 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 Aluminocopiapite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Pale lemon-yellow to deep yellow
Streak:
No data
Hardness:
2 - 3 on Mohs scale
Comment:
by analogy to copiapite group
Tenacity:
Fragile
Cleavage:
Perfect
Perfect on {010}; imperfect on {101}
Perfect on {010}; imperfect on {101}
Density:
2.163 g/cm3 (Calculated)
Optical Data of Aluminocopiapite
Type:
Biaxial (+)
RI values:
nα = 1.525 nβ = 1.535 - 1.54 nγ = 1.585 - 1.59
2V:
Measured: 45° , Calculated: 40°
Max. Birefringence:
δ = 0.060 - 0.065
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 µm 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 µm 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:
Low (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:
none
Pleochroism:
Visible
Comments:
Y = colorless; Z= greenish yellow.
Chemistry of Aluminocopiapite
Mindat Formula:
Al2/3Fe3+4(SO4)6(OH)2 · 20H2O
Element Weights:
Crystallography of Aluminocopiapite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 7.3(1) Å, b = 18.8(2) Å, c = 7.31(1) Å
α = 91.5(2)°, β = 102.3(1)°, γ = 98.7(1)°
α = 91.5(2)°, β = 102.3(1)°, γ = 98.7(1)°
Ratio:
a:b:c = 0.388 : 1 : 0.389
Unit Cell V:
967.14 ų (Calculated from Unit Cell)
Z:
1
Morphology:
As minute scales and efforvescences.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.2 Å | (100) |
| 18.1 Å | (80) |
| 5.58 Å | (80) |
| 6.17 Å | (70) |
| 3.58 Å | (50) |
| 3.50 Å | (50) |
| 5.32 Å | (30) |
Comments:
Magnesium-rich. Forty Mile River, Alaska, USA. Data from Jolly and Foster (1967).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] | |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Geological Setting:
Secondary mineral formed by oxidation of pyrite in coal deposits and shales. May also be of fumarolic origin.
Type Occurrence of Aluminocopiapite
Co-Type Localities:
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 93834, 103544.
Other Language Names for Aluminocopiapite
Relationship of Aluminocopiapite to other Species
Member of:
Other Members of Copiapite Group:
| Calciocopiapite | CaFe3+4(SO4)6(OH)2 · 20H2O | Tric. 1 : P1 |
| Copiapite | Fe2+Fe3+4(SO4)6(OH)2 · 20H2O | Tric. 1 : P1 |
| Cuprocopiapite | Cu2+Fe3+4(SO4)6(OH)2 · 20H2O | Tric. 1 : P1 |
| Ferricopiapite | Fe3+0.67Fe3+4(SO4)6(OH)2 · 20H2O | Tric. 1 : P1 |
| Magnesiocopiapite | MgFe3+4(SO4)6(OH)2 · 20H2O | Tric. 1 : P1 |
| Zincocopiapite | ZnFe3+4(SO4)6(OH)2 · 18H2O | Tric. 1 : P1 |
Common Associates
Associations Based on Photo Data:
| 3 photos of Aluminocopiapite associated with Pickeringite | MgAl2(SO4)4 · 22H2O |
| 2 photos of Aluminocopiapite associated with Woodhouseite | CaAl3(PO4)(SO4)(OH)6 |
| 2 photos of Aluminocopiapite associated with Quartz | SiO2 |
| 2 photos of Aluminocopiapite associated with Rozenite | FeSO4 · 4H2O |
| 2 photos of Aluminocopiapite associated with Melanterite | Fe2+(H2O)6(SO4) · H2O |
| 1 photo of Aluminocopiapite associated with Magnesiocopiapite | MgFe3+4(SO4)6(OH)2 · 20H2O |
| 1 photo of Aluminocopiapite associated with Voltaite | K2Fe2+5Fe3+3Al(SO4)12 · 18H2O |
| 1 photo of Aluminocopiapite associated with Aubertite | CuAl(SO4)2Cl · 14H2O |
| 1 photo of Aluminocopiapite associated with Bonattite | CuSO4 · 3H2O |
| 1 photo of Aluminocopiapite associated with Pyrite | FeS2 |
Related Minerals - Strunz-mindat Grouping
| 7.DB.05 | Svyazhinite | (Mg,Mn2+,Ca)(Al,Fe3+)(SO4)2F · 14H2O |
| 7.DB.05 | Aubertite | CuAl(SO4)2Cl · 14H2O |
| 7.DB.05 | Magnesioaubertite | (Mg,Cu)Al(SO4)2Cl · 14H2O |
| 7.DB.10 | Rostite | Al(SO4)(OH) · 5H2O |
| 7.DB.10 | Khademite | Al(SO4)F · 5H2O |
| 7.DB.15 | Jurbanite | Al(SO4)(OH) · 5H2O |
| 7.DB.20 | Minasragrite | (V4+O)(SO4) · 5H2O |
| 7.DB.20 | Anorthominasragrite | (V4+O)(SO4) · 5H2O |
| 7.DB.20 | Orthominasragrite | (V4+O)(SO4) · 5H2O |
| 7.DB.25 | Bobjonesite | (V4+O)(SO4) · 3H2O |
| 7.DB.27 | Karpovite | Tl2VO(SO4)2(H2O) |
| 7.DB.30 | Metahohmannite | Fe3+2(SO4)2O · 4H2O |
| 7.DB.30 | Hohmannite | Fe3+2(SO4)2O · 8H2O |
| 7.DB.30 | Amarantite | Fe3+2(SO4)2O · 7H2O |
| 7.DB.35 | Calciocopiapite | CaFe3+4(SO4)6(OH)2 · 20H2O |
| 7.DB.35 | Zincocopiapite | ZnFe3+4(SO4)6(OH)2 · 18H2O |
| 7.DB.35 | Copiapite | Fe2+Fe3+4(SO4)6(OH)2 · 20H2O |
| 7.DB.35 | Cuprocopiapite | Cu2+Fe3+4(SO4)6(OH)2 · 20H2O |
| 7.DB.35 | Magnesiocopiapite | MgFe3+4(SO4)6(OH)2 · 20H2O |
| 7.DB.35 | Ferricopiapite | Fe3+0.67Fe3+4(SO4)6(OH)2 · 20H2O |
Other Information
Notes:
Somewhat soluble in water.
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 Aluminocopiapite
mindat.org URL:
https://www.mindat.org/min-87.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Aluminocopiapite
Reference List:
Bandy, Mark C. (1938) Mineralogy of three sulphate deposits of northern Chile. American Mineralogist, 23 (11) 669-760 (Temple Mountain, as copiapite)
Jolly, James H., Foster, Helen L. (1967) X-ray diffraction data of aluminocopiapite. American Mineralogist, 52 (7-8) 1220-1223
Bayliss, P., Atencio, D. (1985) X-ray powder-diffraction data and cell parameters for copiapite-group minerals. The Canadian Mineralogist, 23 (1) 53-56
Majzlan, J., Michallik, R. (2007) The crystal structures, solid solutions and infrared spectra of copiapite-group minerals. Mineralogical Magazine, 71 (5) 553-569 doi:10.1180/minmag.2007.071.5.553
Ogorodova, L. P., Gritsenko, Yu. D., Vigasina, M. F., Kosova, D. A., Melchakova, L. V., Ksenofontov, D. A., Dedushenko, S. K. (2021) Physicochemical and Calorimetric Study of Aluminocopiapite and Thermodynamic Properties of Copiapite-Group Minerals. Geochemistry International, 59 (3) 333-340 doi:10.1134/s0016702921010079
Localities for Aluminocopiapite
Showing 67 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.
Argentina | |
| MIKON and Gunnar Färber catalogues (2005) |
Austria | |
| Niedermayr (1996) |
| Taucher (1993) +1 other reference |
| Postl et al. (1988) +2 other references |
| Arthofer et al. (2025) +1 other reference |
Brazil | |
| Atencio et al. (1994) |
| Gomes et al. (2023) | |
| Rafael Hernandes Corrêa-Silva ... |
| Atencio et al. (2011) | |
Bulgaria | |
| Dimitrova +3 other references |
| Atanassova et al. (2009) |
Canada | |
|
Chessy copper mines, Chessy, Villefranche-sur-Saône, Rhône, Auvergne-Rhône-Alpes, France