Brassite
A valid IMA mineral species
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About Brassite
Formula:
Mg(HAsO4) · 4H2O
Colour:
White
Lustre:
Waxy, Silky, Dull, Earthy
Specific Gravity:
2.28 - 2.33
Crystal System:
Orthorhombic
Name:
Named by François Fontan, Marcel Orliac, François Permingeat, Roland Pierrot, and Réjane Stahl in 1973 for Réjane Brasse, apparently the maiden name of Réjane Stahl, French chemist of Universite de Paris Sud, who first synthesized the compound.
Unique Identifiers
Mindat ID:
756
Long-form identifier:
mindat:1:1:756:8
Similar Names
| Barácite | A synonym of Barićite | |
| Bearsite | A valid IMA mineral species | Be2(AsO4)(OH) · 4H2O |
| Beresite | A rock classification type | |
| Boracite | A valid IMA mineral species - grandfathered | Mg3(B7O13)Cl |
| Brizzite | A synonym of Brizziite | |
| Brossite | A variety of 'Iron-bearing Dolomite' [Dolomite] | Ca(Mg,Fe)(CO3)2 |
| Brucite | A valid IMA mineral species - grandfathered | Mg(OH)2 |
| Brucite (of Dufrénoy) | A synonym of Zincite | |
| Brucite (of Gibbs) | A synonym of Chondrodite | |
| Bursaite | A discredited species name | Pb5Bi4S11 (?) |
IMA Classification of Brassite
Approved
IMA Formula:
Mg(As5+O3OH)·4H2O
Approval year:
1973
First published:
1973
Classification of Brassite
8.CE.15
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
E : With only medium-sized cations, RO4:H2O about 1:2.5
39.1.7.1
39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
1 : A[HXO4]·xH2O
39 : HYDRATED ACID PHOSPHATES,ARSENATES AND VANADATES
1 : A[HXO4]·xH2O
20.2.2
20 : Arsenates (also arsenates with phosphate, but without other anions)
2 : Arsenates of Be, Mg, Ca or Ba
20 : Arsenates (also arsenates with phosphate, but without other anions)
2 : Arsenates of Be, Mg, Ca or Ba
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 |
|---|---|---|
| Bsi | 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 Brassite
Waxy, Silky, Dull, Earthy
Transparency:
Translucent
Comment:
May have a fine satin-like appearance.
Colour:
White
Streak:
White
Comment:
Soft fine-grained mineral. True hardness unknown.
Tenacity:
Brittle
Cleavage:
Perfect
{001} perfect.
{001} perfect.
Fracture:
Irregular/Uneven, Splintery
Density:
2.28 - 2.33 g/cm3 (Measured) 2.326 g/cm3 (Calculated)
Comment:
AC B 32:1460 (1976) structure.
Optical Data of Brassite
Type:
Biaxial (+)
RI values:
nα = 1.531 nβ = 1.546 nγ = 1.562
Birefringence:
0.031
Max. Birefringence:
δ = 0.031
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:
None to Very Low
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.
No measured or calculated 2V is on file for this mineral, so the value used here (89°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (89°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r < v moderate
Optical Extinction:
XYZ=bac; 2V=very large
Pleochroism:
Non-pleochroic
Chemistry of Brassite
Mindat Formula:
Mg(HAsO4) · 4H2O
Element Weights:
Elements listed:
Crystallography of Brassite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pbca
Setting:
Pbca
Cell Parameters:
a = 7.472 Å, b = 10.891 Å, c = 16.585 Å
Ratio:
a:b:c = 0.686 : 1 : 1.523
Unit Cell V:
1,349.65 ų (Calculated from Unit Cell)
Z:
8
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 0009557 | Brassite | Protas J, Gindt R (1976) Structure cristalline de la brassite, MgHAsO4*4H2O, produit de deshydratation de la roesslerite Acta Crystallographica B32 1460-1466 |  | 1976 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.55 Å | (80) |
| 5.45 Å | (80) |
| 4.95 Å | (100) |
| 4.52 Å | (80) |
| 3.98 Å | (80) |
| 3.73 Å | (80) |
| 3.30 Å | (80) |
| 3.08 Å | (100) |
Comments:
ICDD 23-1228 (synthetic), also 29-860 (calculated pattern).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals | |
| 56 : Slag and smelter minerals (see also #51 and #55) |
Type Occurrence of Brassite
General Appearance of Type Material:
crusts of fine grained material
Place of Conservation of Type Material:
Ecole nationale supericure des mines de Paris
Geological Setting of Type Material:
Post-mine alteration of arsenic ore.
Associated Minerals at Type Locality:
Synonyms of Brassite
Other Language Names for Brassite
Common Associates
Associations Based on Photo Data:
| 19 photos of Brassite associated with Rösslerite | Mg(HAsO4) · 7H2O |
| 5 photos of Brassite associated with Picropharmacolite | Ca4Mg(AsO4)2(HAsO4)2 · 11H2O |
| 5 photos of Brassite associated with Pharmacolite | Ca(HAsO4) · 2H2O |
| 1 photo of Brassite associated with Realgar | As4S4 |
| 1 photo of Brassite associated with Native Arsenic | As |
| 1 photo of Brassite associated with Haidingerite | CaHAsO4 · H2O |
Related Minerals - Strunz-mindat Grouping
| 8.CE. | Monteneroite | Cu2+Mn2+2(AsO4)2 · 8H2O |
| 8.CE. | Belmonteite | CaMn2(AsO4)2 · 7H2O |
| 8.CE. | Zincocabrerite | ZnMg2(AsO4)2(H2O)8 |
| 8.CE.X | Babánekite | Cu3(AsO4)2 · 8H2O |
| 8.CE.05 | Chudobaite | Mg5(AsO4)2(AsO3OH)2 · 10H2O |
| 8.CE.05 | Geigerite | Mn2+5(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.10 | Newberyite | Mg(PO3OH) · 3H2O |
| 8.CE.10 | Manganonewberyite | Mn(PO3OH)(H2O)3 |
| 8.CE.15 | Fanguangite | (MoO2)(PO3OH) · 4H2O |
| 8.CE.20 | Phosphorrösslerite | Mg(PO3OH) · 7H2O |
| 8.CE.20 | Rösslerite | Mg(HAsO4) · 7H2O |
| 8.CE.25 | Switzerite | Mn2+3(PO4)2 · 7H2O |
| 8.CE.25 | Metaswitzerite | Mn2+3(PO4)2 · 4H2O |
| 8.CE.30 | Pradetite | CoCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Veselovskýite | ZnCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Lindackerite | CuCu4(AsO4)2(HAsO4)2 · 9H2O |
| 8.CE.30 | Klajite | MnCu4(AsO4)2(HAsO4)2 · 9-10H2O |
| 8.CE.30 | Hloušekite | (Ni,Co)Cu4(AsO4)2(AsO3OH)2 · 9H2O |
| 8.CE.30 | Ondrušite | CaCu4(AsO4)2(HAsO4)2 · 10H2O |
| 8.CE.35 | Bobierrite | Mg3(PO4)2 · 8H2O |
| 8.CE.40 | Barićite | (Mg,Fe)3(PO4)2 · 8H2O |
| 8.CE.40 | Parasymplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Gritsenkoite | CoMg2(AsO4)2(H2O)8 |
| 8.CE.40 | Cabrerite | NiMg2(AsO4)2 · 8H2O |
| 8.CE.40 | Pakhomovskyite | Co3(PO4)2 · 8H2O |
| 8.CE.40 | Vivianite | Fe2+Fe2+2(PO4)2 · 8H2O |
| 8.CE.40 | Arupite | Ni3(PO4)2 · 8H2O |
| 8.CE.40 | Erythrite | Co3(AsO4)2 · 8H2O |
| 8.CE.40 | Hörnesite | Mg3(AsO4)2 · 8H2O |
| 8.CE.40 | Manganohörnesite | Mn2+3(AsO4)2 · 8H2O |
| 8.CE.40 | Köttigite | Zn3(AsO4)2 · 8H2O |
| 8.CE.40 | Ferrisymplesite | Fe3+3(AsO4)2(OH)3 · 5H2O |
| 8.CE.40 | Annabergite | Ni3(AsO4)2 · 8H2O |
| 8.CE.45 | Symplesite | Fe2+3(AsO4)2 · 8H2O |
| 8.CE.50 | Cattiite | Mg3(PO4)2 · 22H2O |
| 8.CE.55 | Koninckite | Fe3+PO4 · 3H2O |
| 8.CE.60 | Kaňkite | FeAsO4 · 3.5H2O |
| 8.CE.60 | Hilarionite | Fe3+2(SO4)(AsO4)(OH) · 6H2O |
| 8.CE.65 | Steigerite | Al(VO4) · 3H2O |
| 8.CE.70 | Metaschoderite | Al2(PO4)(VO4) · 6H2O |
| 8.CE.70 | Schoderite | Al2(PO4)(VO4) · 8H2O |
| 8.CE.75 | Zigrasite | MgZr(PO4)2 · 4H2O |
| 8.CE.75 | 'UM2009-11-PO:CaHZr' | CaZr[PO4]2 · 4H2O |
| 8.CE.75 | Malhmoodite | FeZr(PO4)2 · 4H2O |
| 8.CE.80 | Santabarbaraite | Fe3+3(PO4)2(OH)3 · 5H2O |
| 8.CE.85 | Metaköttigite | (Zn,Fe,Fe)3(AsO4)2 · 8(H2O,OH) |
| 8.CE.90 | Slavkovite | Cu13(AsO4)6(AsO3OH)4 · 23H2O |
Fluorescence of Brassite
Not fluorescent.
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 Brassite
mindat.org URL:
https://www.mindat.org/min-756.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Brassite
Reference List:
Fontan, François, Orliac, Marcel, Permingeat, François, Pierrot, Roland, Stahl, Réjane (1973) La brassite, MgHAsO4 • 4H2O, une nouvelle espèce minérale. Bulletin de Minéralogie, 96 (6) 365-370 doi:10.3406/bulmi.1973.6850
Fleischer, Michael; Mandarino, Joseph A. (1975) New mineral names. American Mineralogist, 60 (9-10). 945-947
Localities for Brassite
Showing 16 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.
Canada | |
| Percival et al. (2007, October) |
| Percival |
Czech Republic (TL) | |
| Bull.Soc.fr.Min.Crist. (1974) |
| Dr. Jan Hlousek label +1 other reference | |
France | |
| Forner et al. (1997) |
| Favreaux (1997) |
Germany | |
| Mineralogical Society of America - ... |
| Mineralogical Society of America - ... |
| Weiß (1990) |
| Weiß (1990) | |
| Möhn et al. (07/2020) |
Greece | |
| Rieck et al. (2020) |
| Rieck et al. (2020) |
Morocco | |
| Georges FAVREAU collection & EDX ... |
Poland | |
| Mineralogical Society of America - ... |
| Cu +2 other references |
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Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic