Protasite
A valid IMA mineral species
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About Protasite
Formula:
Ba(UO2)3O3(OH)2 · 3H2O
Colour:
Light orange, bright orange
Lustre:
Sub-Adamantine
Specific Gravity:
5.827 (Calculated)
Crystal System:
Monoclinic
Name:
Named for Professor Jean Protas (1932–2007), French mineralogist, University of Nancy, Nancy, France, who first synthesized the compound, and for his work with uranium oxide minerals.
This page provides mineralogical data about Protasite.
Unique Identifiers
Mindat ID:
3289
Long-form identifier:
mindat:1:1:3289:2
Similar Names
| Pratesiite | A valid IMA mineral species - pending publication | AgCuTe2 |
IMA Classification of Protasite
Approved
IMA Formula:
Ba(U6+O2)3O3(OH)2·3H2O
Approval year:
1984
First published:
1986
Classification of Protasite
4.GB.10
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
G : Uranyl Hydroxides
B : With additional cations (K, Ca, Ba, Pb, etc.); with mainly UO2(O,OH)5 pentagonal polyhedra
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
G : Uranyl Hydroxides
B : With additional cations (K, Ca, Ba, Pb, etc.); with mainly UO2(O,OH)5 pentagonal polyhedra
5.5.3.1
5 : OXIDES CONTAINING URANIUM OR THORIUM
5 : AX3O10·xH2O
5 : OXIDES CONTAINING URANIUM OR THORIUM
5 : AX3O10·xH2O
7.16.14
7 : Oxides and Hydroxides
16 : Oxides of U
7 : Oxides and Hydroxides
16 : Oxides 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 |
|---|---|---|
| Ps | 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 Protasite
Sub-Adamantine
Transparency:
Transparent
Colour:
Light orange, bright orange
Tenacity:
Brittle
Cleavage:
Distinct/Good
Parallel to {010} good
Parallel to {010} good
Fracture:
Hackly
Density:
5.827(3) g/cm3 (Calculated)
Comment:
Calculated from ideal formula. Using empirical formula gives 5.88 g/cm3.
Optical Data of Protasite
Type:
Biaxial (-)
RI values:
nα = 1.78 nβ = 1.80 - 1.83 nγ = 1.82 - 1.83
2V:
Measured: 60° to 81°
Max. Birefringence:
δ = 0.040 - 0.050
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
Pleochroism:
Not Visible
Comments:
None for Y or Z.
Chemistry of Protasite
Mindat Formula:
Ba(UO2)3O3(OH)2 · 3H2O
Element Weights:
Elements listed:
Crystallography of Protasite
Crystal System:
Monoclinic
Class (H-M):
m - Domatic
Cell Parameters:
a = 12.2949(16) Å, b = 7.2206(10) Å, c = 6.9558(8) Å
β = 90.401(15)°
β = 90.401(15)°
Ratio:
a:b:c = 1.703 : 1 : 0.963
Unit Cell V:
617.50 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Platelets, flattened on {010}
Twinning:
Type description describes striations due to twinning. The twinning is a 60◦ rotation about [010]. Universal.
Comment:
Space Group: P n.
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
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
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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) |
|---|---|---|---|---|---|---|---|
| 0001134 | Protasite | Pagoaga M K, Appleman D E, Stewart J M (1987) Crystal structures and crystal chemistry of the uranyl oxide hydrates becquerelite, billietite, and protasite American Mineralogist 72 1230-1238 |  | 1987 | Shinkolobwe mine, Shaba, Zaire | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.14 Å | (100) |
| 7.06 Å | (50) |
| 3.58 Å | (35) |
| 3.11 Å | (35) |
| 2.496 Å | (35) |
| 2.395 Å | (25) |
| 1.976 Å | (25) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Type Occurrence of Protasite
General Appearance of Type Material:
Bright orange pseudo-hexagonal platelets.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 150732.
Geological Setting of Type Material:
Oxidized zone of a uranium deposit
Associated Minerals at Type Locality:
Synonyms of Protasite
Other Language Names for Protasite
Common Associates
Related Minerals - Strunz-mindat Grouping
| 4.GB.05 | Rameauite | K2Ca(UO2)6O6(OH)4 · 6H2O |
| 4.GB.05 | Agrinierite | K2(Ca,Sr)[(UO2)3O3(OH)2]2 · 5H2O |
| 4.GB.05 | Compreignacite | K2(UO2)6O4(OH)6 · 7H2O |
| 4.GB.10 | Becquerelite | Ca(UO2)6O4(OH)6 · 8H2O |
| 4.GB.10 | Billietite | Ba(UO2)6O4(OH)6 · 4-8H2O |
| 4.GB.15 | Richetite | (Fe3+,Mg)Pb 8.6(UO2)36O36(OH)24 · 41H2O |
| 4.GB.20 | Calciouranoite | (Ca,Ba,Pb)U2O7 · 5H2O |
| 4.GB.20 | Bauranoite | Ba(UO2)2(OH)6 · 1-2H2O |
| 4.GB.20 | Metacalciouranoite | (Ca,Ba,Pb,K2)U2O7 · 2H2O |
| 4.GB.25 | Fourmarierite | Pb(UO2)4O3(OH)4 · 4H2O |
| 4.GB.30 | Wölsendorfite | Pb7(UO2)14O19(OH)4 · 12H2O |
| 4.GB.35 | Masuyite | Pb(UO2)3O3(OH)2 · 3H2O |
| 4.GB.40 | Vandendriesscheite | PbU7O22 · 12H2O |
| 4.GB.40 | Metavandendriesscheite | PbU7O22 · nH2O n < 12 |
| 4.GB.45 | Vandenbrandeite | Cu(UO2)(OH)4 |
| 4.GB.50 | Sayrite | Pb2(UO2)5O6(OH)2 · 4H2O |
| 4.GB.55 | Curite | Pb3(H2O)2[(UO2)4O4(OH)3]2 |
| 4.GB.60 | Iriginite | (UO2)Mo2O7 · 3H2O |
| 4.GB.65 | Uranosphaerite | Bi(UO2)O2(OH) |
| 4.GB.70 | Holfertite | CaxU6+2-xTi(O8-xOH4x) · 3H2O |
| 4.GB.75 | Carlosbarbosaite | (UO2)2Nb2O6(OH)2 · 2H2O |
| 4.GB.80 | Gauthierite | KPb[(UO2)7O5(OH)7] · 8H2O |
| 4.GB.85 | Kroupaite | KPb0.5[(UO2)8O4(OH)10] · 10H2O |
| 4.GB.90 | Leesite | K(H2O)2[(UO2)4O2(OH)5] · 3H2O |
| 4.GB.95 | Shinkolobweite | Pb1.333[U5+O(OH)(UO2)5O4.67(OH)5.33](H2O)5 |
| 4.GB.95 | Nollmotzite | Mg[U5+(U6+O2)2O4F3] · 4H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 65.9075% | 16,476,875 | 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:
radioactive
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 Protasite
mindat.org URL:
https://www.mindat.org/min-3289.html
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References for Protasite
Reference List:
Pagoaga, M. K., Appleman, D. E., Stewart, J. M. (1986) A new barium uranyl oxide hydrate mineral, protasite. Mineralogical Magazine, 50 (355) 125-128 doi:10.1180/minmag.1986.050.355.16
Pagoaga, M. Katherine, Appleman, Daniel E., Stewart, James M. (1987) Crystal structures and crystal chemistry of the uranyl oxide hydrates becquerelite, billietite, and protasite. American Mineralogist, 72 (11-12) 1230-1238
Localities for Protasite
Showing 7 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.
Brazil | |
| Pires et al. (2014) |
DR Congo (TL) | |
| Pagoaga et al. (1987) +2 other references |
Germany | |
| Kolitsch et al. (2000) |
| Markl et al. (2011) |
Italy | |
| Campostrini I. (2013) |
Russia | |
| - (USSR) +2 other references |
Spain | |
| Joan Abella i Creus (Joanabellacreus@gmail.com) |
Quick NavTopAbout ProtasiteUnique IdentifiersSimilar NamesIMA 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
Shinkolobwe Mine, Shinkolobwe, Kambove Territory, Haut-Katanga, DR Congo