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UM1972-01-AsO:BaCaU
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Formula:
Ba-Ca-U-As-O
Crystal System:
Orthorhombic
"Mineral F" from Sophia shaft, Wittichen area, Schwarzwald (Black Forest), Germany.
Forms crusts, associated with metaheinrichite and uranospinite. In the crusts it exists as acicular crystals, up to 40 microns in size and 1 micron thick.
Forms crusts, associated with metaheinrichite and uranospinite. In the crusts it exists as acicular crystals, up to 40 microns in size and 1 micron thick.
Unique Identifiers
Mindat ID:
47250
Long-form identifier:
mindat:1:1:47250:4
Optical Data of UM1972-01-AsO:BaCaU
Type:
Biaxial (-)
RI values:
nα = 1.605 nγ = 1.738
Max. Birefringence:
δ = 0.133
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 Âĩm 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 Âĩm 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.
No measured or calculated 2V is on file for this mineral, so the value used here (87°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (87°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Comments:
colorless (X), yellowish (Z)
Comments:
2V small
Chemistry of UM1972-01-AsO:BaCaU
Mindat Formula:
Ba-Ca-U-As-O
Element Weights:
Crystallography of UM1972-01-AsO:BaCaU
Crystal System:
Orthorhombic
Comment:
crystal system not sure
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.01 Ã | (100) |
| 4.91 Ã | (50) |
| 4.49 Ã | (80) |
| 3.54 Ã | (60) |
| 3.29 Ã | (60) |
| 3.01 Ã | (70) |
| 2.86 Ã | (70) |
| 1.921 Ã | (50) |
| 1.877 Ã | (50) |
Comments:
Different from heinrichite and metaheinrichite
Radioactivity
Fluorescence of UM1972-01-AsO:BaCaU
Other Information
Notes:
Readily dissolves in HCI and HNO3
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 UM1972-01-AsO:BaCaU
mindat.org URL:
https://www.mindat.org/min-47250.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for UM1972-01-AsO:BaCaU
Reference List:
Walenta, Kurt (1972) Die SekundÃĪrmineralien der Co-Ni-Ag-Bi-U-ErzgÃĪnge im Gebiet von Wittichen im mittleren Schwarzwald. Der Aufschluss: 23(9): 279-329.(Abs. in: Fleischer, M. (1973): New mineral names. American Mineralogist: 58: 560-562)
Localities for UM1972-01-AsO:BaCaU
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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.
Germany | |
| Walenta (1972) +1 other reference |
