Pseudomeisserite-(NH4)
A valid IMA mineral species
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About Pseudomeisserite-(NH4)
Formula:
(NH4)2Na4[(UO2)2(SO4)5] · 4H2O
Colour:
Light yellow
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
3.22 (Calculated)
Crystal System:
Monoclinic
Name:
Named for its similarity in appearance to meisserite. The two minerals are virtually indistinguishable in appearance. The (NH4) suffix assumes that at some point in the future, a potassium dominant species will be found and described.
New structure type.
Name Encoding
Formatted:
pseudomeisserite-(NH4)
HTML:
pseudomeisserite-(NH<sub>4</sub>)
LaTeX:
pseudomeisserite-(NH\$\_4\$)
Unique Identifiers
Mindat ID:
53569
Long-form identifier:
mindat:1:1:53569:0
IMA Classification of Pseudomeisserite-(NH4)
Approved
Approval year:
2019
First published:
2020
Type description reference:
Classification of Pseudomeisserite-(NH4)
7.EC.85
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
C : With medium-sized and large 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 |
|---|---|---|
| Pmss-NH4 | 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 Pseudomeisserite-(NH4)
Vitreous
Transparency:
Transparent
Colour:
Light yellow
Streak:
Very pale yellow
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{100}
{100}
Fracture:
Conchoidal
Density:
3.22(2) g/cm3 (Calculated)
Optical Data of Pseudomeisserite-(NH4)
Type:
Biaxial (-)
RI values:
nα = 1.536(2) nβ = 1.559(2) nγ = 1.565(2)
2V:
Measured: 53° (1)
Max. Birefringence:
δ = 0.029
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:
r > v, distinct
Pleochroism:
Visible
Comments:
X colourless, Y light yellow and Z pale yellow
Chemistry of Pseudomeisserite-(NH4)
Mindat Formula:
(NH4)2Na4[(UO2)2(SO4)5] · 4H2O
Element Weights:
Crystallography of Pseudomeisserite-(NH4)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Cell Parameters:
a = 13.1010(3) Å, b = 10.0948(2) Å, c = 19.494(1) Å
β = 104.285(7)°
β = 104.285(7)°
Ratio:
a:b:c = 1.298 : 1 : 1.931
Unit Cell V:
2,498.41 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 12.69 Å | (76) |
| 8.88 Å | (55) |
| 6.83 Å | (84) |
| 6.01 Å | (100) |
| 4.593 Å | (51) |
| 4.414 Å | (57) |
| 3.959 Å | (67) |
| 3.135 Å | (76) |
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] | |
| 47f : [Uranyl (U⁶⁺) minerals] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
Type Occurrence of Pseudomeisserite-(NH4)
General Appearance of Type Material:
light yellow prisms
Place of Conservation of Type Material:
The mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 67621 and 67622
Associated Minerals at Type Locality:
Synonyms of Pseudomeisserite-(NH4)
Other Language Names for Pseudomeisserite-(NH4)
Dutch:Pseudomeisseriet-(NH4)
German:Pseudomeisserit-(NH4)
Common Associates
Associations Based on Photo Data:
| 1 photo of Pseudomeisserite-(NH4) associated with Changoite | Na2Zn(SO4)2 · 4H2O |
| 1 photo of Pseudomeisserite-(NH4) associated with Ferrinatrite | Na3Fe(SO4)3 · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 7.EC. | Nitscheite | (NH4)2[(UO2)2(SO4)3(H2O)2] · 3H2O |
| 7.EC. | Beshtauite | (NH4)2(UO2)(SO4)2 · 2H2O |
| 7.EC. | Oldsite-(K) | K2Fe2+[(UO2)(SO4)2]2(H2O)8 |
| 7.EC. | Adolfpateraite | K(UO2)(SO4)(OH)(H2O) |
| 7.EC. | Libbyite | (NH4)2(Na2◻)[(UO2)2(SO4)3(H2O)]2 · 7H2O |
| 7.EC. | Seaborgite | LiK2Na6(UO2)(SO4)5(SO3OH)(H2O) |
| 7.EC.05 | Zinczippeite | Zn(UO2)2(SO4)O2 · 3.5H2O |
| 7.EC.05 | Zippeite | K3(UO2)4(SO4)2O3(OH) · 3H2O |
| 7.EC.05 | Cobaltzippeite | Co(UO2)2(SO4)O2 · 3.5H2O |
| 7.EC.05 | Nickelzippeite | Ni2(UO2)6(SO4)3(OH)10 · 16H2O |
| 7.EC.05 | Redcanyonite | (NH4)2Mn[(UO2)4O4(SO4)2](H2O)4 |
| 7.EC.05 | Natrozippeite | Na5(UO2)8(SO4)4O5(OH)3 · 12H2O |
| 7.EC.05 | Magnesiozippeite | Mg(UO2)2(SO4)O2 · 3.5H2O |
| 7.EC.05 | Ammoniozippeite | (NH4)2[(UO2)2(SO4)O2] · H2O |
| 7.EC.05 | Plavnoite | K0.8Mn0.6[(UO2)2O2(SO4)] · 3.5H2O |
| 7.EC.10 | Rabejacite | Ca(UO2)4(SO4)2(OH)6 · 6H2O |
| 7.EC.10 | Svornostite-(NH4) | (NH4)2Mg(UO2)2(SO4)4(H2O)8 |
| 7.EC.10 | Svornostite-(K) | K2Mg[(UO2)(SO4)2]2(H2O)8 |
| 7.EC.15 | Sejkoraite-(Y) | Y2(UO2)8(SO4)4O6(OH)2 · 26H2O |
| 7.EC.15 | Marécottite | Mg3(UO2)8(SO4)4O6(OH)2 · 28H2O |
| 7.EC.15 | Hubbardite | Mg(H2O)6[(UO2)2O(OH)(SO4)]2 · 8H2O |
| 7.EC.20 | Pseudojohannite | Cu3(UO2)4(SO4)2O4(OH)2 · 12H2O |
| 7.EC.40 | Bluelizardite | Na7(UO2)(SO4)4Cl(H2O)2 |
| 7.EC.45 | Meisserite | Na5(UO2)(SO4)3(SO3OH)(H2O) |
| 7.EC.45 | Fermiite | Na4(UO2)(SO4)3 · 3H2O |
| 7.EC.45 | Oppenheimerite | Na2(UO2)(SO4)2 · 3H2O |
| 7.EC.50 | Feynmanite | Na(UO2)(SO4)(OH) · 3.5H2O |
| 7.EC.50 | Plášilite | Na(UO2)(SO4)(OH) · 2H2O |
| 7.EC.55 | Geschieberite | K2(UO2)(SO4)2 · 2H2O |
| 7.EC.60 | Ottohahnite | Na6(UO2)2(SO4)5(H2O)7 · 1.5H2O |
| 7.EC.65 | Péligotite | Na6(UO2)(SO4)4 · 4H2O |
| 7.EC.70 | Klaprothite | Na6(UO2)(SO4)4 · 4H2O |
| 7.EC.75 | Lussierite | Na10[(UO2)(SO4)4](SO4)2 · 3(H2O) |
| 7.EC.80 | Navrotskyite | K2Na10(UO2)3(SO4)9 · 2H2O |
| 7.EC.90 | Wetherillite | Na2Mg(UO2)2(SO4)4 · 18H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 39.0062% | 9,751,550 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 0.0000% | 0 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Fluorescence of Pseudomeisserite-(NH4)
Fluorescence is bright lime green under 405 nm ultraviolet light.
Other Information
Notes:
The mineral is easily soluble in H2O
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 Pseudomeisserite-(NH4)
mindat.org URL:
https://www.mindat.org/min-53569.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 Pseudomeisserite-(NH4)
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Mills, Stuart J. (2019) New minerals and nomenclature modifications approved in 2019. CNMNC Newsletter 49. Mineralogical Magazine, 83 (3) 479-483 doi:10.1180/mgm.2019.35
Localities for Pseudomeisserite-(NH4)
Showing 1 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.
USA (TL) | |
| Miyawaki et al. (2019) +2 other references |
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Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA