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Moluranite

A valid IMA mineral species - grandfathered
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About MoluraniteHide

Formula:
H4U4+(UO2)3(MoO4)7 · 18H2O
Colour:
Black
Lustre:
Resinous
Hardness:
3 - 4
Specific Gravity:
4.
Crystal System:
Amorphous
Name:
Named for the composition, that includes MOLybdenum and URANium.
This page provides mineralogical data about Moluranite.


Unique IdentifiersHide

Mindat ID:
2744
Long-form identifier:
mindat:1:1:2744:7

IMA Classification of MoluraniteHide

Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
H4U4+(U6+O2)3(Mo6+O4)7·18H2O
First published:
1959

Classification of MoluraniteHide

7.HA.15

7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
H : Uranium and uranyl molybdates and wolframates
A : With U4+
49.1.2.1

49 : HYDRATED MOLYBDATES AND TUNGSTATES
1 : Acid Hydrated Molybdates and Tungstates
27.3.9

27 : Sulphites, Chromates, Molybdates and Tungstates
3 : Molybdates

Mineral SymbolsHide

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

SymbolSourceReference for Standard
MluIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of MoluraniteHide

Resinous
Transparency:
Translucent
Colour:
Black
Comment:
Brown in thin fragments
Hardness:
3 - 4 on Mohs scale
Tenacity:
Brittle
Density:
4. g/cm3 (Measured)    

Optical Data of MoluraniteHide

Type:
Isotropic
RI values:
n = 1.97 - 1.98
Surface Relief:
Very High (positive)
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
Colour in reflected light:
pale gray

Chemistry of MoluraniteHide

Mindat Formula:
H4U4+(UO2)3(MoO4)7 · 18H2O
Element Weights:
Element% weight
U38.144 %
O33.331 %
Mo26.911 %
H1.615 %

Calculated from ideal end-member formula.
U
O
Mo
H

Crystallography of MoluraniteHide

Crystal System:
Amorphous
Comment:
Amorphous

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
4.17 Å(10)
1.314 Å(6)
1.305 Å(6)
3.44 Å(5)
2.58 Å(5)
2.12 Å(5)
2.03 Å(5)

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Stage 7: Great Oxidation Event<2.4
47a : [Near-surface hydration of prior minerals]
47f : [Uranyl (U⁶⁺) minerals]

Type Occurrence of MoluraniteHide

Other Language Names for MoluraniteHide

German:Moluranit
Spanish:Moluranita

Related Minerals - Strunz-mindat GroupingHide

7.HA.05SedoviteU(MoO4)2Orth.
7.HA.10CousiniteMgU2Mo2O11 · 6H2O

RadioactivityHide

Radioactivity:
Element % Content Activity (Bq/kg) Radiation Type
Uranium (U) 38.1438% 9,535,950 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:

DistanceDose rateRisk
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

Other InformationHide

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 MoluraniteHide

References for MoluraniteHide

Localities for MoluraniteHide

Showing 6 localities.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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Locality ListHide

- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.
China
 
  • Guizhou
    • Qianxinan
      • Xingyi County
Mingfa Zhang et al. (2005)
  • Hebei
    • Zhangjiakou
      • Guyuan County
MENG et al. (2010)
Egypt
 
  • Red Sea Governorate
Hussein et al. (1988)
  • South Sinai Governorate
    • Abu Zeneima (Abu Zenima)
Bisher (2012)
Mexico
 
  • Sonora
    • Bacoachi Municipality
      • Bacoachi
Analysis by and from the collection of ...
Russia (TL)
 
  • Aldan Shield
    • Chara and Tokko Rivers Confluence
      • Torgo River Basin
Pekov (1998)
 
and/or  
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