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Bulachite
A valid IMA mineral species
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About Bulachite
Neubulach, Germany
Formula:
Al6(AsO4)3(OH)9(H2O)4 · 2H2O
Originally assumed be Al2(AsO4)(OH)3 · 3H2O.
Colour:
White to blue-green
Hardness:
2
Specific Gravity:
2.60
Crystal System:
Orthorhombic
Name:
Named for the type locality at Neubulach, Baden Württemberg, Germany.
A rare secondary Al arsenate hydrate.
Grey et al. (2020) show that bulachite from Cap Garonne has the formula Al6(AsO4)3(OH)9(H2O)4⋅2H2O and is intergrown with a higher hydrate with composition Al6(AsO4)3(OH)9(H2O)4⋅8H2O. The latter was later named galeaclolusite.
Grey et al. (2020) show that bulachite from Cap Garonne has the formula Al6(AsO4)3(OH)9(H2O)4⋅2H2O and is intergrown with a higher hydrate with composition Al6(AsO4)3(OH)9(H2O)4⋅8H2O. The latter was later named galeaclolusite.
Unique Identifiers
Mindat ID:
799
Long-form identifier:
mindat:1:1:799:3
IMA Classification of Bulachite
Approved
IMA Formula:
Al6(As5+O4)3(OH)9(H2O)4·2H2O
Approval year:
1982
First published:
1983
Classification of Bulachite
8.DE.15
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
E : With only medium-sized cations, (OH, etc.):RO4 = 3:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
E : With only medium-sized cations, (OH, etc.):RO4 = 3:1
42.6.7.2
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
20.4.2
20 : Arsenates (also arsenates with phosphate, but without other anions)
4 : Arsenates of Group III metals (Al, rare earths)
20 : Arsenates (also arsenates with phosphate, but without other anions)
4 : Arsenates of Group III metals (Al, rare earths)
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 |
|---|---|---|
| Buh | 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 Bulachite
Transparency:
Translucent
Comment:
Lustre is Satiny
Colour:
White to blue-green
Streak:
White
Hardness:
2 on Mohs scale
Cleavage:
None Observed
Density:
2.60 g/cm3 (Measured) 2.55 g/cm3 (Calculated)
Optical Data of Bulachite
Type:
Biaxial (-)
RI values:
nα = 1.54 nβ = 1.546 nγ = 1.548
2V:
Measured: 66° , Calculated: 58°
Max. Birefringence:
δ = 0.008
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.
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
Chemistry of Bulachite
Mindat Formula:
Al6(AsO4)3(OH)9(H2O)4 · 2H2O
Originally assumed be Al2(AsO4)(OH)3 · 3H2O.
Originally assumed be Al2(AsO4)(OH)3 · 3H2O.
Element Weights:
Elements listed:
Crystallography of Bulachite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 15.3994(3) Å, b = 17.6598(3) Å, c = 7.8083(1) Å
Ratio:
a:b:c = 0.872 : 1 : 0.442
Unit Cell V:
2,123.47 ų (Calculated from Unit Cell)
Comment:
Cell from Grey et al. (2020). Cell of type material: a = 15.53, b = 17.78, c = 7.03 Å.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.78 Å | (100) |
| 3.49 Å | (80) |
| 8.97 Å | (70) |
| 6.55 Å | (70) |
| 5.92 Å | (70) |
| 3.75 Å | (70) |
| 2.73 Å | (60) |
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 |
Type Occurrence of Bulachite
General Appearance of Type Material:
Exceedingly fine-grained needles in radial
aggregates encrusting quartz
aggregates encrusting quartz
Place of Conservation of Type Material:
Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Stuttgart, Germany, numbers BU1,27.
Associated Minerals at Type Locality:
Synonyms of Bulachite
Other Language Names for Bulachite
Common Associates
Associations Based on Photo Data:
| 2 photos of Bulachite associated with Goethite | Fe3+O(OH) |
| 1 photo of Bulachite associated with Azurite | Cu3(CO3)2(OH)2 |
| 1 photo of Bulachite associated with Malachite | Cu2(CO3)(OH)2 |
| 1 photo of Bulachite associated with Bariopharmacoalumite | Ba0.5Al4(AsO4)3(OH)4 · 4H2O |
| 1 photo of Bulachite associated with Mansfieldite | AlAsO4 · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 8.DE. | Arsenoveszelyite | Cu2Zn(AsO4)(OH)3 · 2H2O |
| 8.DE. | Kipushite | (Cu,Zn)5Zn(PO4)2(OH)6 · H2O |
| 8.DE. | Goldhillite | Cu5Zn(AsO4)2(OH)6 · H2O |
| 8.DE.05 | Senegalite | Al2(PO4)(OH)(OH)2 · H2O |
| 8.DE.10 | Fluellite | Al2(PO4)F2(OH) · 7H2O |
| 8.DE.20 | Zapatalite | Cu3Al4(PO4)3(OH)9 · 4H2O |
| 8.DE.25 | Ceruleite | Cu2Al7(AsO4)4(OH)13 · 11.5H2O |
| 8.DE.30 | Veszelyite | (Cu,Zn)2Zn(PO4)(OH)3 · 2H2O |
| 8.DE.35 | Philipsburgite | Cu5Zn(AsO4)(PO4)(OH)6 · H2O |
| 8.DE.40 | Juanitaite | (Cu,Ca,Fe)10Bi(AsO4)4(OH)11 · 2H2O |
| 8.DE.45 | Iangreyite | Ca2Al7(PO4)2(PO3OH)2(OH,F)15 · 8H2O |
Other Information
Notes:
Easily soluble in HCl (1:1),less easily in HNO3 (1:1)
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 Bulachite
mindat.org URL:
https://www.mindat.org/min-799.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Bulachite
Reference List:
Fleischer, M.; Mandarino, J.A.; Pabst, A. (1980) New mineral names. American Mineralogist, 65 (1-2). 205-210
Dunn, Pete J., Chao, George Y., Fleischer, Michael, Ferraiolo, James A., Langley, Richard H., Pabst, Adolf, Zilczer, Janet A. (1985) New mineral names. American Mineralogist, 70 (1-2) 214-221
Anthony, John W., Bideaux, Richard A., Bladh, Kenneth W., Nichols, Monte C. - Eds. (2016) Handbook of Mineralogy. https://www.handbookofmineralogy.org/
Grey, Ian E., Yoruk, Emre, Kodjikian, Stéphanie, Klein, Holger, Bougerol, Catherine, Brand, Helen E.A., Bordet, Pierre, Mumme, William G., Favreau, Georges, Mills, Stuart J. (2020) Bulachite, [Al6(AsO4)3(OH)9(H2O)4]⋅2H2O from Cap Garonne, France: Crystal structure and formation from a higher hydrate. Mineralogical Magazine, 84 (4) 608-615 doi:10.1180/mgm.2020.52
Localities for Bulachite
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.
France | |
| Favreau et al. (2014) +2 other references |
| Favreau et al. (2024) | |
Germany (TL) | |
| Walenta (1983) +1 other reference |
| Weiß (1990) |
Greece | |
| Schusser et al. (2022) |
Italy | |
| Frau et al. (2001) |
UK | |
| collections.museumvictoria.com.au (n.d.) +1 other reference |
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Cap Garonne Mine, Le Pradet, Toulon, Var, Provence-Alpes-Côte d'Azur, France