登录
Compreignacite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Compreignacite
Formula:
K2(UO2)6O4(OH)6 · 7H2O
Colour:
Yellow, orange-yellow
Lustre:
Sub-Vitreous, Resinous, Waxy, Greasy
Specific Gravity:
5.03
Crystal System:
Orthorhombic
Name:
Named for the community of Compreignac, France, near the type locality.
Crystals tend to be small (< 1mm), platy, and translucent and occur on fracture surfaces with black uraninite. The color is yellow to orange-yellow and the luster grades from waxy to dull, rarely bright.
Unique Identifiers
Mindat ID:
1117
Long-form identifier:
mindat:1:1:1117:0
IMA Classification of Compreignacite
Approved
IMA Formula:
K2(U6+O2)6O4(OH)6·7H2O
Approval year:
1964
First published:
1964
Classification of Compreignacite
4.GB.05
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
5.7.1.1
5 : OXIDES CONTAINING URANIUM OR THORIUM
7 : AX6O19·xH2O
5 : OXIDES CONTAINING URANIUM OR THORIUM
7 : AX6O19·xH2O
7.16.8
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 |
|---|---|---|
| Cgn | 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 Compreignacite
Sub-Vitreous, Resinous, Waxy, Greasy
Transparency:
Transparent, Translucent
Colour:
Yellow, orange-yellow
Streak:
Pale yellow
Tenacity:
Brittle
Cleavage:
Perfect
(001)
(001)
Density:
5.03(5) g/cm3 (Measured) 5.13(5) g/cm3 (Calculated)
Optical Data of Compreignacite
Type:
Biaxial (-)
RI values:
nα = 1.789 nβ = 1.798 nγ = 1.802
2V:
Measured: 10° to 15°
Birefringence:
0.013
Max. Birefringence:
δ = 0.013
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 medium
Pleochroism:
Strong
Comments:
X(=c) colorless; Y(=a), Z(=b) yellow
Chemistry of Compreignacite
Mindat Formula:
K2(UO2)6O4(OH)6 · 7H2O
Element Weights:
Elements listed:
Crystallography of Compreignacite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnnm
Cell Parameters:
a = 7.161 Å, b = 12.190 Å, c = 14.847 Å
Ratio:
a:b:c = 0.587 : 1 : 1.218
Unit Cell V:
1,296.03 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Flattened on (001)
Twinning:
Common on (110)
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
Remove metal-metal sticks
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
Black Background | White Background
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) |
|---|---|---|---|---|---|---|---|
| 0005561 | Compreignacite | Burns P C (1998) The structure of compreignacite, K2((UO2)3O2(OH)3)2(H2O)7 The Canadian Mineralogist 36 1061-1067 |  | 1998 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.46 Å | (100) |
| 6.23 Å | (3) |
| 6.03 Å | (3) |
| 5.71 Å | (3) |
| 4.72 Å | (5) |
| 4.594 Å | (9) |
| 3.712 Å | (80) |
| 3.579 Å | (40) |
| 3.534 Å | (60) |
| 3.378 Å | (5) |
| 3.226 Å | (70) |
| 3.197 Å | (90) |
| 3.097 Å | (1) |
| 3.043 Å | (3) |
| 3.027 Å | (3) |
| 2.886 Å | (5) |
| 2.844 Å | (3) |
| 2.821 Å | (5) |
| 2.579 Å | (20) |
| 2.564 Å | (35) |
| 2.475 Å | (13) |
| 2.373 Å | (3) |
| 2.321 Å | (8) |
| 2.294 Å | (3) |
| 2.246 Å | (3) |
| 2.215 Å | (4) |
| 2.204 Å | (4) |
| 2.090 Å | (6) |
| 2.058 Å | (15) |
| 2.032 Å | (35) |
| 1.985 Å | (20) |
| 1.960 Å | (10) |
| 1.929 Å | (7) |
| 1.884 Å | (1) |
| 1.862 Å | (1) |
| 1.856 Å | (10) |
| 1.800 Å | (12) |
| 1.781 Å | (7) |
| 1.768 Å | (3) |
Comments:
ICDD 33-1049 Synthetic
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 Compreignacite
Place of Conservation of Type Material:
University of Pierre and Marie Curie, Paris.
National School of Mines, Paris, France.
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 165183.
National School of Mines, Paris, France.
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 165183.
Associated Minerals at Type Locality:
Synonyms of Compreignacite
Other Language Names for Compreignacite
Common Associates
Associations Based on Photo Data:
| 11 photos of Compreignacite associated with Gypsum | CaSO4 · 2H2O |
| 5 photos of Compreignacite associated with Uraninite | UO2 |
| 5 photos of Compreignacite associated with Pseudojohannite | Cu3(UO2)4(SO4)2O4(OH)2 · 12H2O |
| 4 photos of Compreignacite associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 4 photos of Compreignacite associated with Zeunerite | Cu(UO2)2(AsO4)2 · 12H2O |
| 3 photos of Compreignacite associated with Schoepite | (UO2)8O2(OH)12 · 12H2O |
| 2 photos of Compreignacite associated with Leesite | K(H2O)2[(UO2)4O2(OH)5] · 3H2O |
| 2 photos of Compreignacite associated with Rutherfordine | (UO2)CO3 |
| 2 photos of Compreignacite associated with Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
| 1 photo of Compreignacite associated with Microcline | K(AlSi3O8) |
Related Minerals - Strunz-mindat Grouping
| 4.GB. | Leishmanite | Ba(H2O)4[(UO2)3O2(OH)3]2 · 3H2O |
| 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.10 | Becquerelite | Ca(UO2)6O4(OH)6 · 8H2O |
| 4.GB.10 | Billietite | Ba(UO2)6O4(OH)6 · 4-8H2O |
| 4.GB.10 | Protasite | Ba(UO2)3O3(OH)2 · 3H2O |
| 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) | 71.7491% | 17,937,275 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 3.9285% | 1,218 | 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 Compreignacite
Weakly fluorescent green in SWUV. Slightly brighter green fluorescence in LWUV. Distinctive green (not yellow-green) fluorescence in both SW-LED and LW-LED.
Other Information
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 Compreignacite
mindat.org URL:
https://www.mindat.org/min-1117.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Compreignacite
Reference List:
Protas, Jean (1964) Une nouvelle espèce minérale : la compreignacite, K2O·6UO3·11H2O. Bulletin de Minéralogie, 87 (3) 365-371 doi:10.3406/bulmi.1964.5750
Granger, Marie-Magdeleine, Protas, Jean (1965) Étude de la structure cristalline de la compreignacite. Bulletin de Minéralogie, 88 (2) 211-213 doi:10.3406/bulmi.1965.5837
Burns, P. C. (1998) The structure of compreignacite, K2[(UO2)3O2(OH)3]2(H2O)7. The Canadian Mineralogist, 36 (4) 1061-1067
Localities for Compreignacite
Showing 41 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.
Australia | |
| Geosciences |
| Bottrill (2021) +1 other reference |
Brazil | |
| Pires et al. (2014) |
China | |
| Zhao et al. (2026) |
Czech Republic | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Plasil (2005) |
| Hloušek et al. (2002) |
| Möhn et al. (12/2021) | |
| Plášil et al. (2014) |
| Sejkora et al. (2013) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| 70 (in German) +2 other references | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
France (TL) | |
| Bull.Soc.fr.Min.Crist. (1964) |
| Collection Frédéric Bonnet |
| Collection Frédéric Bonnet |
Germany | |
| Walenta (1996) |
| Desor (05/2020) |
| Former Fritz Rüger collection |
| Witzke et al. (1998) |
Hungary | |
| Zsombor Eva |
Italy | |
| Ghizzoni et al. (2005) |
| Ghizzoni et al. (2005) | |
| Boscardin et al. (1982) | |
| Olmi F. |
Namibia | |
| Bowell et al. (2017) |
New Zealand | |
| XRD ID by BM (NH) |
Slovakia | |
| Martin Števko-unpublished |
Spain | |
| MTI Mineralogía Topográfica Ibérica +1 other reference |
Switzerland | |
| Meisser (2012) |
| Meisser (2012) |
| N. Meisser +1 other reference |
UK | |
| Elton et al. (1994) +1 other reference |
| Elton et al. (1994) +1 other reference | |
| P Haas |
USA | |
| Färber (n.d.) |
| www.seltene-mineralien.de (n.d.) | |
| Eckel et al. (1997) | |
| Nashua Min Soc. Disp. Cat. 1995 +1 other reference |
| Min News 14:7 p1 |
| Min News 16:1 p1 |
Quick NavTopAbout CompreignaciteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
Giftkies adit, Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic