Barrotite
A valid IMA mineral species
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About Barrotite
Dôme du Barrot, France
Formula:
Cu9Al(HSiO4)2[(SO4)(HAsO4)0.5](OH)12 · 8H2O
Colour:
Intense blue
Lustre:
Adamantine, Vitreous
Hardness:
2
Specific Gravity:
2.90
Crystal System:
Trigonal
Name:
Named for the Dôme du Barrot.
Unique Identifiers
Mindat ID:
43860
Long-form identifier:
mindat:1:1:43860:7
Similar Names
| Bairdite | A valid IMA mineral species | Pb2Cu42+Te26+O10(OH)2(SO4) · H2O |
| Barattiite | A synonym of 'Unnamed (Pb-Fe Chloride Hydroxide Hydrate)' | |
| Barettite | near (Ca,Mg,Fe)6Si5O16 · 0.5H2O | |
| Baritite | A synonym of Baryte | |
| Barronite | A valid IMA mineral species | (◻0.5Ba0.5)(UO2)2Si5O12(OH) · 2H2O |
| Buratite | A synonym of Aurichalcite | |
| Burtite | A valid IMA mineral species | Ca[Sn(OH)6] |
IMA Classification of Barrotite
Approved
IMA Formula:
Cu2+9Al(HSiO4)2(S6+O4)(HAs5+O4)0.5(OH)12·8H2O
Approval year:
2011
First published:
2014
Classification of Barrotite
7.DE.45
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
E : With only medium-sized cations; unclassified
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
D : Sulfates (selenates, etc.) with additional anions, with H2O
E : With only medium-sized cations; unclassified
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 |
|---|---|---|
| Bro | 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 Barrotite
Adamantine, Vitreous
Transparency:
Transparent, Translucent
Colour:
Intense blue
Streak:
Pale blue
Hardness:
2 on Mohs scale
Tenacity:
Flexible
Cleavage:
Perfect
Micaceous cleavage on (001)
Micaceous cleavage on (001)
Fracture:
Irregular/Uneven
Density:
2.90(2) g/cm3 (Measured) 2.977 g/cm3 (Calculated)
Optical Data of Barrotite
Type:
Uniaxial (-)
RI values:
nω = 1.652(2) nε = 1.576(2)
Max. Birefringence:
δ = 0.076
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:
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Visible
Comments:
ω=blue ε=light blue
Chemistry of Barrotite
Mindat Formula:
Cu9Al(HSiO4)2[(SO4)(HAsO4)0.5](OH)12 · 8H2O
Element Weights:
Crystallography of Barrotite
Crystal System:
Trigonal
Class (H-M):
3 - Pyramidal
Cell Parameters:
a = 10.650(2) Å, c = 21.954(7) Å
Ratio:
a:c = 1 : 2.061
Unit Cell V:
2156.5 ų
Z:
3
Morphology:
Hexagonal, tabular on (001). Forms {001} and {110}.
Twinning:
Twinning not observed.
Comment:
Space Group P31 or P32
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.34 Å | (100) |
| 3.670 Å | (90) |
| 2.645 Å | (90) |
| 2.587 Å | (30) |
| 2.396 Å | (25) |
| 2.278 Å | (15) |
| 1.537 Å | (50) |
| 1.331 Å | (20) |
Comments:
From Type Description.
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] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] |
Type Occurrence of Barrotite
General Appearance of Type Material:
Perfect hexagonal plates of maximum size 0.5x0.02 mm or grouped in aggregates to 2 mm in size.
Place of Conservation of Type Material:
Aydin Adnan Menderes Üniversitesi, Memnune Inci Meslek Yüksek Okulu, Karacasu-Aydin, Turkey, specimen number KMY-26, and the Laboratory of Crystallography, University of Geneva, Switzerland, specimen number CR-011.
Geological Setting of Type Material:
In sandstone.
Associated Minerals at Type Locality:
Synonyms of Barrotite
Other Language Names for Barrotite
Common Associates
Associations Based on Photo Data:
| 1 photo of Barrotite associated with Connellite | Cu19(SO4)(OH)32Cl4 · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 7.DE. | Magnesioalterite | Mg2Fe3+4(SO4)4(C2O4)2(OH)4 · 17H2O |
| 7.DE. | Fabritzite | Zn9(SO4)2(OH)12Cl2 · 6H2O |
| 7.DE. | Cossaite | (Mg0.5,◻)Al6(SO4)6(HSO4)F6 · 36H2O |
| 7.DE. | Downsite | K2(MoO3)3(SO4) · 4H2O |
| 7.DE. | Liangjunite | K2(Mo2O5)(SO4)2 · 3H2O |
| 7.DE.05 | Mangazeite | Al2(SO4)(OH)4 · 3H2O |
| 7.DE.10 | 'UKI-1975-(SO:AlCu)' | (Cu, Al, SO4, H2O) |
| 7.DE.10 | Carbonatecyanotrichite | Cu4Al2(CO3,SO4)(OH)12 · 2H2O |
| 7.DE.10 | Cyanotrichite | Cu4Al2(SO4)(OH)12 · 2H2O |
| 7.DE.15 | Schwertmannite | Fe3+16(OH,SO4)12-13O16 · 10-12H2O |
| 7.DE.20 | Tlalocite | Cu10Zn6(Te6+O4)2(Te4+O3)(OH)25Cl · 27H2O |
| 7.DE.25 | Utahite | MgCu4Zn2Te6+3O14(OH)4 · 6H2O |
| 7.DE.35 | Coquandite | Sb6+xO8+x(SO4)(OH)x(H2O)1- x (x = 0.3) |
| 7.DE.40 | Osakaite | Zn4(SO4)(OH)6 · 5H2O |
| 7.DE.42 | Alterite | Zn2Fe3+4(SO4)4(C2O4)2(OH)4 · 17H2O |
| 7.DE.45 | Wilcoxite | MgAl(SO4)2F · 17H2O |
| 7.DE.47 | Tiberiobardiite | {Cu9Al[SiO3(OH)]2(OH)12(H2O)6}(SO4)1.5 · 10H2O |
| 7.DE.50 | Bouškaite | (MoO2)2O(SO3OH)2(H2O)4 |
| 7.DE.50 | Stanleyite | (V4+O)(SO4) · 6H2O |
| 7.DE.57 | 'Khangalasite' | Fe(SO4)(OH) · 2H2O |
| 7.DE.60 | Hydrobasaluminite | Al4(SO4)(OH)10 · 12-36H2O |
| 7.DE.62 | Volaschioite | Fe4(SO4)O2(OH)6 · 2H2O |
| 7.DE.65 | Zaherite | Al12(SO4)5(OH)26 · 20H2O |
| 7.DE.75 | Camérolaite | Cu6Al3(OH)18(H2O)2[Sb(OH)6](SO4) |
Fluorescence of Barrotite
Not fluorescent.
Other Information
Notes:
Soluble in HCl.
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 Barrotite
mindat.org URL:
https://www.mindat.org/min-43860.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Barrotite
Localities for Barrotite
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.
France | |
| Cahier de l'AFM N° 3 2017 |
| Williams et al. (2013) +1 other reference |
Norway | |
| Husdal (2021) |
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Mont-Roc Mine, Mont-Roc, Castres, Tarn, Occitanie, France