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Magnanelliite
A valid IMA mineral species
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About Magnanelliite
Formula:
K3Fe3+2(SO4)4(OH)(H2O)2
Colour:
Yellow to orange‐yellow
Lustre:
Vitreous
Hardness:
3
Specific Gravity:
2.82
Crystal System:
Monoclinic
Name:
The name honors Stefano Magnanelli (b. 1959), chemist and mineral collector, for his contributions to the knowledge of the mineralogy of the Apuan Alps hydrothermal veins. He coauthored the type description of bottinoite and provided the first specimens of parasterryit and bianchiniite, as well as several samples from the Carrara marble quarries and other mining sites of the Apuan Alps, supporting the mineralogical studies of these occurrences.
Unique Identifiers
Mindat ID:
53578
Long-form identifier:
mindat:1:1:53578:8
IMA Classification of Magnanelliite
Approved
IMA Formula:
K3Fe3+2(S6+O4)4(OH)(H2O)2
Approval year:
2019
First published:
2019
Classification of Magnanelliite
7.DF.57
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
F : With large and medium-sized cations
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 |
|---|---|---|
| Mgn | 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 Magnanelliite
Vitreous
Transparency:
Transparent
Colour:
Yellow to orange‐yellow
Streak:
Pale yellow
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on {010}, fair on {100}.
Good on {010}, fair on {100}.
Fracture:
Irregular/Uneven, Conchoidal
Density:
2.82(3) g/cm3 (Measured) 2.883 g/cm3 (Calculated)
Optical Data of Magnanelliite
Type:
Biaxial (+)
RI values:
nα = 1.628(2) nβ = 1.637(2) nγ = 1.665(2)
2V:
Measured: 60° (2), Calculated: 59.9°
Max. Birefringence:
δ = 0.037
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:
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:
Strong dispersion, r > v.
Optical Extinction:
Y = b; X ∧ c ≈ 25° in the obtuse angle β.
Pleochroism:
Visible
Comments:
X = orange yellow, Y and Z = yellow.
Comments:
Absorption: X > Y ~ Z.
Chemistry of Magnanelliite
Mindat Formula:
K3Fe3+2(SO4)4(OH)(H2O)2
Element Weights:
Crystallography of Magnanelliite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 7.5491(3) Å, b = 16.8652(6) Å, c = 12.1574(4) Å
β = 94.064(1)°
β = 94.064(1)°
Ratio:
a:b:c = 0.448 : 1 : 0.721
Unit Cell V:
1,543.95 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.9 Å | (m) |
| 4.91 Å | (mw) |
| 3.612 Å | (mw) |
| 3.427 Å | (mw) |
| 3.300 Å | (mw) |
| 3.085 Å | (s) |
| 3.006 Å | (m) |
| 2.704 Å | (m) |
Reference:
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] |
Type Occurrence of Magnanelliite
General Appearance of Type Material:
Steeply terminated prisms, up to 0.5 mm in length.
Place of Conservation of Type Material:
Type material is deposited in the mineralogical collections of the Museo di Storia Naturale,Università di Pisa, Via Roma 79, Calci (Pisa, Italy), catalogue number 19894 (holotype), and the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue number 67241 (cotype).
Geological Setting of Type Material:
Oxidation of pyrite orebody.
Associated Minerals at Type Locality:
Synonyms of Magnanelliite
Other Language Names for Magnanelliite
Dutch:Magnanelliiet
German:Magnanelliit
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 7.DF. | Siligiite | [Pb(H2O)5(SO4)][Zn9(OH)18] |
| 7.DF. | Alcaparrosaite | K3Ti4+Fe3+(SO4)4O(H2O)2 |
| 7.DF. | Flaggite | Pb4Cu2+4Te6+2(SO4)2O11(OH)2(H2O) |
| 7.DF. | Bairdite | Pb2Cu2+4Te6+2O10(OH)2(SO4) · H2O |
| 7.DF. | Tzeferisite | CaZn8(SO4)2(OH)12Cl2(H2O)9 |
| 7.DF. | Cherokeeite | [Pb2Zn(OH)4](SO4) · H2O |
| 7.DF. | Ammoniomathesiusite | (NH4)5(UO2)4(SO4)4(VO5) · 4H2O |
| 7.DF. | Sigogglinite | [Pb6Zn(OH)8]2(SO4)6 · (H2O)8-x |
| 7.DF.X | Blueridgeite | [Pb8Zn3Cu2+(OH)16](SO4)2(S2O3)2 · 2H2O |
| 7.DF. | Erssonite | Mg7Fe3+2(OH)18[Ca(H2O)6](SO4)2 · 12H2O |
| 7.DF. | Poellmannite | Ca6Al3(OH)18[Na(H2O)6](SO4)2 · 6H2O |
| 7.DF. | Carlsonite | (NH4)5Fe3+3O(SO4)6 · 7H2O |
| 7.DF. | Cuprocherokeeite | [Pb8Zn3Cu2+(OH)16](SO4)4 · 4H2O |
| 7.DF. | Haywoodite | [Pb(H2O)10][Zn12(OH)20(H2O)(SO4)3] |
| 7.DF. | Chromschieffelinite | Pb10Te6+6O20(OH)14(CrO4)(H2O)5 |
| 7.DF.05 | Uklonskovite | NaMg(SO4)F · 2H2O |
| 7.DF.10 | Kainite | KMg(SO4)Cl · 3H2O |
| 7.DF.10 | Kaliochalcite | KCu2(SO4)2[(OH)(H2O)] |
| 7.DF.15 | Natrochalcite | NaCu2(SO4)2(OH) · 2H2O |
| 7.DF.17 | Genplesite | Ca3Sn(SO4)2(OH)6 · 3H2O |
| 7.DF.17 | 'Unnamed (Ba-Sb Silicate-Sulphate-Hydroxide-Hydrate)' | Ba3Sb5+[(Si,S)O3(OH)]2(OH,O)6 · 3H2O |
| 7.DF.20 | Sideronatrite | Na2Fe(SO4)2(OH) · 3H2O |
| 7.DF.20 | Metasideronatrite | Na2Fe(SO4)2(OH) · H2O |
| 7.DF.25 | Fleischerite | Pb3Ge(SO4)2(OH)6 · 3H2O |
| 7.DF.25 | Mallestigite | Pb3Sb5+(SO4)(AsO4)(OH)6 · 3H2O |
| 7.DF.25 | Schaurteite | Ca3Ge(SO4)2(OH)6 · 4H2O |
| 7.DF.25 | Despujolsite | Ca3Mn4+(SO4)2(OH)6 · 3H2O |
| 7.DF.30 | Slavíkite | (H3O+)3Mg6Fe15(SO4)21(OH)18 · 98H2O |
| 7.DF.35 | Metavoltine | K2Na6Fe2+Fe3+6O2(SO4)12 · 18H2O |
| 7.DF.40 | Lannonite | Mg2Ca4Al4(SO4)8F8 · 24H2O |
| 7.DF.40 | Vlodavetsite | AlCa2(SO4)2F2Cl · 4H2O |
| 7.DF.45 | Peretaite | Ca(SbO)4(SO4)2(OH)2 · 2H2O |
| 7.DF.50 | Gordaite | NaZn4(SO4)(OH)6Cl · 6H2O |
| 7.DF.50 | Calamaite | Na2TiO(SO4)2 · 2H2O |
| 7.DF.52 | Huizingite-(Al) | [(NH4)9(SO4)2][(Al,Fe3+)3(OH)2(H2O)4(SO4)6] |
| 7.DF.52 | Scordariite | K8(Fe3+0.67◻0.33)[Fe3+3O(SO4)6]2 · 14H2O |
| 7.DF.55 | Clairite | (NH4)2Fe3(SO4)4(OH)3 · 3H2O |
| 7.DF.55 | Giacovazzoite | K5Fe3+3O(SO4)6 · 10H2O |
| 7.DF.60 | Arzrunite | Cu4Pb2(SO4)(OH)4Cl6 · 2H2O (?) |
| 7.DF.60 | Evdokimovite | Tl4(VO)3(SO4)5(H2O)5 |
| 7.DF.62 | Bridgesite-(Ce) | CaCe2Cu6(SO4)4(OH)12 · 8H2O |
| 7.DF.65 | Elyite | Pb4Cu(SO4)O2(OH)4 · H2O |
| 7.DF.70 | Yecoraite | Fe3+3Bi5(Te6+O4)2(Te4+O3)O9 · 9H2O |
| 7.DF.70 | Lautenthalite | PbCu4(SO4)2(OH)6 · 3H2O |
| 7.DF.75 | Riomarinaite | Bi(SO4)(OH) · H2O |
| 7.DF.80 | Dukeite | Bi3+24Cr6+8O57(OH)6 · 3H2O |
Monte Arsiccio Mine, Sant'Anna di Stazzema, Stazzema, Lucca Province, Tuscany, Italy