Mbobomkulite
A valid IMA mineral species
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About Mbobomkulite
Formula:
(Ni,Cu)Al4((NO3)2,SO4)(OH)12 · 3H2O
Colour:
Pale sky-blue; colorless under the microscope
Specific Gravity:
2.30
Crystal System:
Monoclinic
Member of:
Name:
For the type locality, the Mbobo Mkulu cave.
Unique Identifiers
Mindat ID:
2608
Long-form identifier:
mindat:1:1:2608:2
IMA Classification of Mbobomkulite
Approved
IMA Formula:
(Ni2+,Cu2+)Al4(N5+O3,S6+O4)2(OH)12·3H2O
Approval year:
1979
First published:
1980
Classification of Mbobomkulite
5.ND.10
5 : CARBONATES (NITRATES)
N : NITRATES
D : With OH (etc.) and H2O
5 : CARBONATES (NITRATES)
N : NITRATES
D : With OH (etc.) and H2O
Dana 7th ed.:
19.2.4.1
19.1.4.1
19 : NITRATES CONTAINING HYDROXYL OR HALOGEN
1 : Anhydrous Nitrates Containing Hydroxyl or Halogen
19 : NITRATES CONTAINING HYDROXYL OR HALOGEN
1 : Anhydrous Nitrates Containing Hydroxyl or Halogen
13.11
13 : Nitrates
13 : Nitrates
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 |
|---|---|---|
| Mbb | 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 Mbobomkulite
Transparency:
Translucent
Comment:
Macroscopically powdery
Colour:
Pale sky-blue; colorless under the microscope
Cleavage:
Perfect
{001}
{001}
Density:
2.30 g/cm3 (Measured) 2.344 g/cm3 (Calculated)
Optical Data of Mbobomkulite
Type:
Biaxial
RI values:
nα = 1.515 nγ = 1.585
Max. Birefringence:
δ = 0.070
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:
Low (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
Dispersion:
relatively weak
Chemistry of Mbobomkulite
Mindat Formula:
(Ni,Cu)Al4((NO3)2,SO4)(OH)12 · 3H2O
Element Weights:
Crystallography of Mbobomkulite
Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Setting:
P21
Cell Parameters:
a = 10.17 Å, b = 8.86 Å, c = 17.14 Å
β = 95.37°
β = 95.37°
Ratio:
a:b:c = 1.148 : 1 : 1.935
Unit Cell V:
1,537.64 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Pseudohexagonal, very thin plates about 10 microns across, piled up along the c axis as well as forming rosettes.
Comment:
Space group is by analogy to chalcoalumite.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.550 Å | (100) |
| 4.271 Å | (40) |
| 7.87 Å | (15) |
| 4.549 Å | (15) |
| 3.179 Å | (15) |
| 3.054 Å | (15) |
| 2.512 Å | (15 |
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] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 52 : Guano- and urine-derived minerals | <0.4 |
Type Occurrence of Mbobomkulite
General Appearance of Type Material:
Pale blue nodules.
Place of Conservation of Type Material:
Museum of the Geological Survey, Pretoria, South Africa.
Geological Setting of Type Material:
A cave located immediately below palaeokarst residual breccia ("giant chert").
Associated Minerals at Type Locality:
Synonyms of Mbobomkulite
Other Language Names for Mbobomkulite
Dutch:Mbobomkuliet
German:Mbobomkulit
Simplified Chinese:硫硝镍铝石
Spanish:Mbobomkulita
Traditional Chinese:硫硝鎳鋁石
Relationship of Mbobomkulite to other Species
Member of:
Other Members of Chalcoalumite Group:
| Chalcoalumite | CuAl4(SO4)(OH)12 · 3H2O | Mon. 2 : P21 |
| Kyrgyzstanite | ZnAl4(SO4)(OH)12 · 3H2O | Mon. 2/m : P21/b |
| Nickelalumite | NiAl4(SO4)(OH)12(H2O)3 | Mon. 2/m |
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 5.ND.05 | Likasite | Cu3(NO3)(OH)5 · 2H2O |
| 5.ND.15 | Hydrombobomkulite | (Ni,Cu)Al4((NO3)2,SO4)(OH)12 · 13-14H2O |
| 5.ND.20 | Sveite | (K3-x◻x)Al8(NO3)6O8Cl4 · nH2O |
| 5.ND.25 | Lislkirchnerite | Pb6Al(OH)8Cl2(NO3)5 · 2H2O |
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 Mbobomkulite
mindat.org URL:
https://www.mindat.org/min-2608.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 Mbobomkulite
Reference List:
Localities for Mbobomkulite
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.
Japan | |
| LIN et al. (2020) |
South Africa (TL) | |
| Ann.Geol.Surv.S.Africa (1980) +1 other reference |
USA | |
| Vochten et al. (2001) |
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Jomac Mine, White Canyon Mining District, San Juan County, Utah, USA