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Hügelite
A valid IMA mineral species - grandfathered
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About Hügelite
Friedrich von Hugel
Formula:
Pb2(UO2)3(AsO4)2O2 · 5H2O
Colour:
Brown, orange-yellow, yellowish brown
Lustre:
Adamantine, Greasy
Hardness:
2 - 3
Specific Gravity:
5.1
Crystal System:
Monoclinic
Member of:
Name:
After Baron Friedrich von Hügel (1852–1925), Austrian-British theologian.
This page provides mineralogical data about Hügelite.
Name Encoding
ASCII-7:
Hugelite
Unique Identifiers
Mindat ID:
1942
Long-form identifier:
mindat:1:1:1942:8
Similar Names
| Augelite | A valid IMA mineral species - grandfathered | Al2(PO4)(OH)3 |
Classification of Hügelite
Phosphuranylite sheet topology
The sheet topology exhibited by members of the phosphuranylite group.
IMA Classification of Hügelite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+2(U6+O2)3(As5+O4)2O2·5H2O
First published:
1914
8.EC.15
8 : PHOSPHATES, ARSENATES, VANADATES
E : Uranyl phosphates and arsenates
C : UO2:RO4 = 3:2
8 : PHOSPHATES, ARSENATES, VANADATES
E : Uranyl phosphates and arsenates
C : UO2:RO4 = 3:2
42.4.5.2
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
4 : (AB)5(XO4)2Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
4 : (AB)5(XO4)2Zq·xH2O
20.7.16
20 : Arsenates (also arsenates with phosphate, but without other anions)
7 : Arsenates of U
20 : Arsenates (also arsenates with phosphate, but without other anions)
7 : Arsenates of U
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 |
|---|---|---|
| Hüg | 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 Hügelite
Adamantine, Greasy
Transparency:
Transparent, Translucent
Colour:
Brown, orange-yellow, yellowish brown
Streak:
Light yellow
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Good on {100}
Probable on {110}
Good on {100}
Probable on {110}
Fracture:
Conchoidal
Density:
5.1 g/cm3 (Measured) 5.8 g/cm3 (Calculated)
Optical Data of Hügelite
Type:
Biaxial (+)
RI values:
nα = 1.898 nγ = 1.915
2V:
Measured: 25°
Max. Birefringence:
δ = 0.017
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 extreme
Pleochroism:
Strong
Comments:
X= yellow
Y= yellow with orange tint
Z= colorless to pale yellow
Y= yellow with orange tint
Z= colorless to pale yellow
Chemistry of Hügelite
Mindat Formula:
Pb2(UO2)3(AsO4)2O2 · 5H2O
Element Weights:
Crystallography of Hügelite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P121/m1
Cell Parameters:
a = 7.0189(7) Å, b = 17.1374(10) Å, c = 8.1310(10) Å
β = 108.904(10)°
β = 108.904(10)°
Ratio:
a:b:c = 0.41 : 1 : 0.474
Unit Cell V:
925.29 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals prismatic [001], with {110}, {001} and {011}.
Twinning:
Twinning by reticular merohedry, mirror in [100]
Comment:
Cell parameters from Plášil et al. (2021)
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.73 Å | (100b) |
| 3.06 Å | (90) |
| 3.00 Å | (70) |
| 2.89 Å | (70) |
| 1.833 Å | (70) |
| 4.33 Å | (60b) |
| 2.70 Å | (60) |
Comments:
Michael mine, Germany.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Type Occurrence of Hügelite
General Appearance of Type Material:
Aggregates of fine, tangled needles. Sometimes in radial arrangements.
Geological Setting of Type Material:
Secondary mineral in hornstone breccia
Synonyms of Hügelite
Other Language Names for Hügelite
Relationship of Hügelite to other Species
Member of:
Krunkelbach Valley Uranium deposit, Menzenschwand, St Blasien, Waldshut, Freiburg Region, Baden-Württemberg, Germany