Moctezumite
A valid IMA mineral species
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About Moctezumite
Formula:
Pb(UO2)(TeO3)2
Colour:
Bright orange, brownish orange to dark orange.
Lustre:
Dull
Hardness:
3
Specific Gravity:
5.73
Crystal System:
Monoclinic
Name:
Named for the type locality, La Moctezuma mine, and the nearest town, Moctezuma, Sonora, Mexico.
Unique Identifiers
Mindat ID:
2737
Long-form identifier:
mindat:1:1:2737:9
IMA Classification of Moctezumite
Approved
IMA Formula:
Pb2+(U6+O2)(Te4+O3)2
Approval year:
1965
First published:
1965
Type description reference:
Classification of Moctezumite
4.JK.65
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
K : Tellurites without additional anions, without H2O
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
J : Arsenites, antimonites, bismuthites, sulfites, selenites, tellurites; iodates
K : Tellurites without additional anions, without H2O
Dana 7th ed.:
34.1.6.1
34.1.5.1
34 : SELENITES, TELLURITES AND SULFITES
1 : A(XO3)
34 : SELENITES, TELLURITES AND SULFITES
1 : A(XO3)
28.3.20
28 : Selenites, Selenates, Tellurites, and Tellurates
3 : Tellurites
28 : Selenites, Selenates, Tellurites, and Tellurates
3 : Tellurites
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 |
|---|---|---|
| Moc | 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 Moctezumite
Dull
Transparency:
Translucent
Colour:
Bright orange, brownish orange to dark orange.
Comment:
Brownish orange in crystals that have been slightly altered
Hardness:
3 on Mohs scale
Cleavage:
Perfect
(100)
(100)
Density:
5.73 g/cm3 (Measured) 7.256 g/cm3 (Calculated)
Optical Data of Moctezumite
Type:
Biaxial (-)
RI values:
nα = 2.11 nβ = 2.11 nγ = 2.11
2V:
Measured: 5° to 10°
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.
Comments:
RIs are minimums
Chemistry of Moctezumite
Mindat Formula:
Pb(UO2)(TeO3)2
Element Weights:
Elements listed:
Crystallography of Moctezumite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 7.813(5) Å, b = 7.061(2) Å, c = 13.775(4) Å
β = 93.71(2)°
β = 93.71(2)°
Ratio:
a:b:c = 1.107 : 1 : 1.951
Unit Cell V:
758.34 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Blade like
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Big Balls | Small Balls | Just Balls | Spacefill
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Display Options
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Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
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Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0001608 | Moctezumite | Swihart G H, Sen Gupta P K, Schlemper E O, Back M E, Gaines R V (1993) The crystal structure of moctezumite [PbUO2](TeO3)2 American Mineralogist 78 835-839 |  | 1993 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.156 Å | (100) |
| 3.492 Å | (90) |
| 2.997 Å | (80) |
| 3.088 Å | (70) |
| 3.385 Å | (60) |
| 2.012 Å | (50) |
| 1.949 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47e : [Vanadates, chromates, manganates] | |
| 47f : [Uranyl (U⁶⁺) minerals] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Moctezumite
General Appearance of Type Material:
Minute blades and rosettes in cracks and vugs in oxidized ore zone.
Place of Conservation of Type Material:
Natural History Museum, Paris, France, 175.84.
Harvard University, Cambridge, Massachusetts, 119086.
National Museum of Natural History, Washington, D.C., USA, 128392, 164345, 164346.
Harvard University, Cambridge, Massachusetts, 119086.
National Museum of Natural History, Washington, D.C., USA, 128392, 164345, 164346.
Geological Setting of Type Material:
Tellurium-gold deposit
Associated Minerals at Type Locality:
Synonyms of Moctezumite
Other Language Names for Moctezumite
Common Associates
Associations Based on Photo Data:
| 8 photos of Moctezumite associated with Emmonsite | Fe3+2(TeO3)3 · 2H2O |
| 5 photos of Moctezumite associated with Schmitterite | (UO2)(TeO3) |
| 4 photos of Moctezumite associated with Quartz | SiO2 |
| 2 photos of Moctezumite associated with Burckhardtite | Pb2(Fe3+Te6+)[AlSi3O8]O6 |
Related Minerals - Strunz-mindat Grouping
| 4.JK. | Matthiasweilite | PbTe4+O3 |
| 4.JK.05 | Walfordite | (Fe3+,Te6+)Te4+3O8 |
| 4.JK.05 | Winstanleyite | TiTe4+3O8 |
| 4.JK.10 | Zincospiroffite | Zn2Te4+3O8 |
| 4.JK.10 | Spiroffite | Mn2+2Te4+3O8 |
| 4.JK.15 | Balyakinite | Cu(TeO3) |
| 4.JK.20 | Rajite | Cu(Te4+2O5) |
| 4.JK.25 | Carlfriesite | CaTe4+2Te6+O8 |
| 4.JK.30 | Chenzhangruite | MnFe2+Te4+4O10 |
| 4.JK.30 | Stankeithite | Mn2+Mn2+Te4+4 O10 |
| 4.JK.30 | Paulhlavaite | CaCuTe4+ 4O10 |
| 4.JK.30 | Denningite | CaMn2+Te4+4O10 |
| 4.JK.35 | Chekhovichite | Bi2Te4+4O11 |
| 4.JK.40 | Smirnite | Bi2Te4+O5 |
| 4.JK.45 | Choloalite | (Cu,Sb)3(Pb,Ca)3(TeO3)6Cl |
| 4.JK.50 | Fairbankite | Pb2+12(Te4+O3)11(SO4) |
| 4.JK.55 | Plumbotellurite | Pb(TeO3) |
| 4.JK.60 | Magnolite | [Hg2]2+[Te4+O3] |
| 4.JK.70 | Schmitterite | (UO2)(TeO3) |
| 4.JK.75 | Cliffordite | (UO2)Te4+3O7 |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 28.7327% | 7,183,175 | 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
Other Information
Notes:
Readily soluble in dilute hydrochloric acid and in dilute sodium hydroxide.
Radiactive.
Radiactive.
Health Risks:
Radioactive
Internet Links for Moctezumite
mindat.org URL:
https://www.mindat.org/min-2737.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Moctezumite
Reference List:
Gaines, Richard V. (1965) Moctezumite, a new lead uranyl tellurite. American Mineralogist, 50 (9) 1158-1163
Swihart, George H., Gupta, Pradip K. Sen, Schlemper, Elmer O., Back, Malcolm E., Gaines, Richard V. (1993) The crystal structure of moctezumite [PbUO2](TeO3)2. American Mineralogist, 78 (7-8) 835-839
Localities for Moctezumite
Showing 3 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.
Mexico | |
| |
| Gaines (1965) |
USA | |
| Robert M. Housley (2005) |
Quick NavTopAbout MoctezumiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Moctezuma Mine, Moctezuma, Moctezuma Municipality, Sonora, Mexico