Alpeite
A valid IMA mineral species
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About Alpeite
Formula:
Ca4Mn3+2Al2(Mn3+Mg)(SiO4)2(Si3O10)(V5+O4)(OH)6
Colour:
Brownish red
Lustre:
Vitreous, Silky
Hardness:
5½ - 6
Specific Gravity:
3.374 (Calculated)
Crystal System:
Orthorhombic
Member of:
Name:
Named for the type locality, Monte Alpe mine, Italy.
The Ca(Mn3+2Al2)-Mn3+ analogue of ardennite-(V).
At the type locality it crystallized from V- and Mn-rich hydrothermal fluids in an oxidizing environment.
In the structure of alpeite, Mn3+ is the dominant cation in the M1 site and is the dominant trivalent cation in the M3 site, while in all other members of the ardennite group, Al is the dominant cation in the M1 site and is the dominant trivalent cation in the M3 site.
At the type locality it crystallized from V- and Mn-rich hydrothermal fluids in an oxidizing environment.
In the structure of alpeite, Mn3+ is the dominant cation in the M1 site and is the dominant trivalent cation in the M3 site, while in all other members of the ardennite group, Al is the dominant cation in the M1 site and is the dominant trivalent cation in the M3 site.
Unique Identifiers
Mindat ID:
50779
Long-form identifier:
mindat:1:1:50779:4
Similar Names
| Alipite | (Ni,Mg)3Si4O10(OH)2 · nH2O |
IMA Classification of Alpeite
Approved
Approval year:
2016
First published:
2017
Type description reference:
Classification of Alpeite
9.BJ.40
9 : SILICATES (Germanates)
B : Sorosilicates
J : Sorosilicates with Si3O10, Si4O11, etc. anions; cations in octahedral [6] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
J : Sorosilicates with Si3O10, Si4O11, etc. anions; cations in octahedral [6] and greater coordination
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 |
|---|---|---|
| Apt | 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 Alpeite
Vitreous, Silky
Transparency:
Transparent
Colour:
Brownish red
Streak:
Beige
Hardness:
5½ - 6 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect cleavage on {1 0 0} and good cleavages on {0 1 0 and {0 0 1}
Perfect cleavage on {1 0 0} and good cleavages on {0 1 0 and {0 0 1}
Parting:
With a curved and stepped fracture
Density:
3.374 g/cm3 (Calculated)
Optical Data of Alpeite
Type:
Biaxial (-)
RI values:
nα = 1.747(3) nβ = 1.785(3) nγ = 1.808(3)
2V:
Measured: 73°
Max. Birefringence:
δ = 0.061
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:
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, strong
Pleochroism:
Visible
Comments:
Y>Z>X in shades of reddish brown
Chemistry of Alpeite
Mindat Formula:
Ca4Mn3+2Al2(Mn3+Mg)(SiO4)2(Si3O10)(V5+O4)(OH)6
Element Weights:
Crystallography of Alpeite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pmmn
Cell Parameters:
a = 8.942(1) Å, b = 6.0534(6) Å, c = 18.978(2) Å
Ratio:
a:b:c = 1.477 : 1 : 3.135
Unit Cell V:
1027.29 ų
Z:
2
Morphology:
Intergrowths of plates, flattened on {1 0 0} and exhibiting the forms {1 0 0}, {0 0 1}, {0 1 2} and {1 0 2}.
Comment:
Space group setting is Pnmm
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.049 Å | (52) |
| 3.259 Å | (51) |
| 3.022 Å | (93) |
| 2.673 Å | (100) |
| 2.572 Å | (69) |
| 2.095 Å | (53) |
| 1.677 Å | (52) |
| 1.511 Å | (83) |
Reference:
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Alpeite
General Appearance of Type Material:
Intergrowths of plates, flattened on {1 0 0} and exhibiting the forms {1 0 0}, {0 0 1}, {0 1 2} and {1 0 2}.
Place of Conservation of Type Material:
Mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA (catalogue number 66288)
Empirical Formula of Type Material:
(Ca3.84Mn2+0.16)Σ4.00(Mn3+1.33Al0.67)Σ2.00(Al1.29Mn3+0.60V5+0.10)Σ1.99(Mn3+0.70Mg0.65Al0.42Co2+0.20)Σ1.97(SiO4)2(Si3O10)[(V5+0.75Si0.25)O4](OH)6
Reference:
Synonyms of Alpeite
Other Language Names for Alpeite
Relationship of Alpeite to other Species
Member of:
Other Members of Ardennite Group:
| Ardennite-(As) | Mn2+4Al4(AlMg)(AsO4)(SiO4)2(Si3O10)(OH)6 | Orth. mmm(2/m2/m2/m) |
| 'Ardennite-(Si)' | ~Mn2+4Al4(AlMg)(SiO4,AsO4)(SiO4)2(Si3O10)(OH)6 | |
| Ardennite-(V) | Mn2+4Al4(AlMg)(VO4)(SiO4)2(Si3O10)(OH)6 | Orth. mmm(2/m2/m2/m) : Pmmn |
| Kannanite | Ca4Al4(AlMg)(VO4)(SiO4)2(Si3O10)(OH)6 | Orth. mmm(2/m2/m2/m) : Pmmn |
Common Associates
Related Minerals - Strunz-mindat Grouping
| 9.BJ. | Arsenmedaite | Mn2+6 As5+Si5O18(OH) |
| 9.BJ.05 | Orientite | Ca8Mn3+10(SiO4)3(Si3O10)3(OH)10 · 4H2O |
| 9.BJ.10 | Rosenhahnite | HCa3[Si3O9(OH)] |
| 9.BJ.15 | Trabzonite | Ca4(Si3O9)(OH)2 |
| 9.BJ.20 | Thalénite-(Y) | Y3Si3O10F |
| 9.BJ.25 | Tiragalloite | Mn2+4As5+Si3O12(OH) |
| 9.BJ.30 | Medaite | Mn2+6V5+Si5O18(OH) |
| 9.BJ.35 | Strontioruizite | Sr2Mn3+2Si4O11(OH)4 · 2H2O |
| 9.BJ.35 | Ruizite | Ca2Mn3+2[Si4O11(OH)2](OH)2 · 2H2O |
| 9.BJ.35 | Taniajacoite | SrCaMn3+2Si4O11(OH)4 · 2H2O |
| 9.BJ.40 | Ardennite-(As) | Mn2+4Al4(AlMg)(AsO4)(SiO4)2(Si3O10)(OH)6 |
| 9.BJ.40 | Kannanite | Ca4Al4(AlMg)(VO4)(SiO4)2(Si3O10)(OH)6 |
| 9.BJ.40 | Ardennite-(V) | Mn2+4Al4(AlMg)(VO4)(SiO4)2(Si3O10)(OH)6 |
| 9.BJ.45 | Kilchoanite | Ca6(SiO4)(Si3O10) |
| 9.BJ.50 | Prismatine | (◻,Fe,Mg)(Mg,Al,Fe)5Al4Si2(Si,Al)2(B,Si,Al)(O,OH,F)22 |
| 9.BJ.50 | Kornerupine | Mg3Al6(Si,Al,B)5O21(OH) |
| 9.BJ.55 | Zunyite | Al13Si5O20(OH,F)18Cl |
| 9.BJ.60 | Hubeite | Ca2Mn2+Fe3+Si4O12(OH) · 2H2O |
| 9.BJ.65 | Cassagnaite | (Ca,Mn2+)4(Fe3+,Mn3+,Al)4(V3+,Mg,Al)2(Si3O10)(SiO4)2(OH,O)8 |
| 9.BJ.70 | Pavlovskyite | Ca8(SiO4)2(Si3O10) |
Other Information
Notes:
Inert in concentrated HCl at room temperature
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 Alpeite
mindat.org URL:
https://www.mindat.org/min-50779.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
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References for Alpeite
Reference List:
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2016) New minerals and nomenclature modifications approved in 2016, CNMNC Newsletter No 34. Mineralogical Magazine, 80 (7) 1315-1321 doi:10.1180/minmag.2016.080.086
Localities for Alpeite
Showing 5 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.
Italy | |
| analysed by Dr. Anthony Kampf +1 other reference |
| Castellaro-Kampf |
| Christophe Boutry collection +1 other reference |
| Fabrizio Castellaro dealer label (co-author on alpeite type paper) |
| Hålenius et al. (2016) +2 other references |
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Scrava Mine, Statale, Ne, Genoa, Liguria, Italy