Kanemite
A valid IMA mineral species
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About Kanemite
Formula:
HNaSi2O5 · 3H2O
Colour:
Colorless to cloudy white; light tan possibly due to inclusions
Lustre:
Sub-Vitreous, Resinous, Waxy, Greasy
Hardness:
4
Specific Gravity:
1.93
Crystal System:
Orthorhombic
Name:
Named in 1972 by Gilbert Maglione and Z. Johan after the type locality at Andajia, Kanem (Khanem) Region, Lake Chad, Chad.
Type Locality:
Cleaved aggregates may appear similar to gypsum.
May dehydrate to Unnamed (Kanemite-related mineral).
May dehydrate to Unnamed (Kanemite-related mineral).
Unique Identifiers
Mindat ID:
2152
Long-form identifier:
mindat:1:1:2152:0
Similar Names
| Kaneite | MnAs |
IMA Classification of Kanemite
Classification of Kanemite
9.EF.25
9 : SILICATES (Germanates)
E : Phyllosilicates
F : Single nets with 6-membered rings, connected by M[4], M[8], etc.
9 : SILICATES (Germanates)
E : Phyllosilicates
F : Single nets with 6-membered rings, connected by M[4], M[8], etc.
73.1.5.1
73 : PHYLLOSILICATES Condensed Tetrahedral Sheets
1 : Condensed Tetrahedral Sheets with double layers
73 : PHYLLOSILICATES Condensed Tetrahedral Sheets
1 : Condensed Tetrahedral Sheets with double layers
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 |
|---|---|---|
| Knm | 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 Kanemite
Sub-Vitreous, Resinous, Waxy, Greasy
Transparency:
Transparent
Colour:
Colorless to cloudy white; light tan possibly due to inclusions
Streak:
White
Hardness:
4 on Mohs scale
Hardness Data:
Measured
Tenacity:
Brittle
Cleavage:
Perfect
{010} perfect; {100} good
{010} perfect; {100} good
Density:
1.93 g/cm3 (Measured) 1.933 g/cm3 (Calculated)
Optical Data of Kanemite
Type:
Biaxial (-)
RI values:
nα = 1.451(2) nβ = 1.470(2) nγ = 1.478(2)
2V:
Measured: 46° , Calculated: 64°
Birefringence:
0.027
Max. Birefringence:
δ = 0.027
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 (negative)
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 distinct
Optical Extinction:
parallel, XYZ = bac
Pleochroism:
Non-pleochroic
Chemistry of Kanemite
Mindat Formula:
HNaSi2O5 · 3H2O
Element Weights:
Elements listed:
Common Impurities:
Al,Ca,K
Crystallography of Kanemite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 7.282 Å, b = 20.507 Å, c = 4.956 Å
Ratio:
a:b:c = 0.355 : 1 : 0.242
Unit Cell V:
740.09 ų (Calculated from Unit Cell)
Z:
4
Comment:
Pnmb
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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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) |
|---|---|---|---|---|---|---|---|
| 0006765 | Kanemite | Vortmann S, Rius J, Marler B, Gies H (1999) Structure solution from powder data of the hydrous layer silicate kanemite, a precursor of the industrial ion exchanger SKS-6 European Journal of Mineralogy 11 125-134 | 1999 | 0 | 293 | ||
| 0002274 | Kanemite | Garvie L A J, Devouard B, Groy T L, Camara F, Buseck P R (1999) Crystal structure of kanemite, NaHSi2O5.3H2O, from the Aris phonolite, Namibia American Mineralogist 84 1170-1175 |  | 1999 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.3 Å | (100) |
| 4.01 Å | (100) |
| 3.44 Å | (90) |
| 3.16 Å | (70) |
| 3.09 Å | (70) |
| 2.48 Å | (80) |
| 2.39 Å | (60) |
| 2.00 Å | (50) |
Comments:
Originally described as monoclinic.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Geological Setting:
Evaoprites
Type Occurrence of Kanemite
General Appearance of Type Material:
Spherical aggregates, generally < 0.3 mm. The surface of the aggregates may show etched to incised surface markings.
Place of Conservation of Type Material:
National School of Mines, Paris, France.
National Museum of Natural History, Washington, D.C., USA, 123219, 142501.
National Museum of Natural History, Washington, D.C., USA, 123219, 142501.
Geological Setting of Type Material:
Interdunary depression. Evaporite.
Associated Minerals at Type Locality:
Synonyms of Kanemite
Other Language Names for Kanemite
Common Associates
Associations Based on Photo Data:
| 4 photos of Kanemite associated with Tuperssuatsiaite | Fe3+Fe3+2(Na◻)◻2Si8O20(OH)2(H2O)4 · 2H2O |
| 3 photos of Kanemite associated with Natrolite | Na2Al2Si3O10 · 2H2O |
| 2 photos of Kanemite associated with Villiaumite | NaF |
| 1 photo of Kanemite associated with Cryolite | Na2NaAlF6 |
| 1 photo of Kanemite associated with 'Unnamed (Fe-analogue of Zakharovite)' | Na4Fe5Si10O24(OH)6 · 6H2O |
Related Minerals - Strunz-mindat Grouping
| 9.EF.05 | Petalite | LiAl(Si4O10) |
| 9.EF.10 | Sanbornite | BaSi2O5 |
| 9.EF.15 | Searlesite | Na(H2BSi2O7) |
| 9.EF.20 | Silinaite | NaLiSi2O5 · 2H2O |
| 9.EF.30 | Yakovenchukite-(Y) | K3NaCaY2[Si12O30] · 4H2O |
Fluorescence of Kanemite
Not fluorescent
Other Information
Notes:
Dilute HCl removes sodium, leaving a hydrated silica.
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 Kanemite
mindat.org URL:
https://www.mindat.org/min-2152.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Kanemite
Reference List:
Johan, Zdenek, Maglione, Gilbert (1972) La kanemite, nouveau silicate de sodium hydraté de néoformation. Bulletin de Minéralogie, 95 (3) 371-382 doi:10.3406/bulmi.1972.6691
Périnet, Guy, Tiercelin, Jean-Jacques, Barton, Charles Edward (1982) Présence de kanemite dans les sédiments récents du Lac Bogoria, Rift Gregory, Kenya. Bulletin de Minéralogie, 105 (6) 633-639 doi:10.3406/bulmi.1982.7646
Almond, Graham G., Harris, Robin K., Franklin, Kevin R. (1997) A structural consideration of kanemite, octosilicate, magadiite and kenyaite. Journal of Materials Chemistry, 7. 681-687 doi:10.1039/a606856a
Vortmann, Sllke, Rius, Jordi, Marler, Bernd, Gies, Hermann (1999) Structure solution from powder data of the hydrous layer silicate kanemite, a precursor of the industrial ion exchanger SKS-6. European Journal of Mineralogy, 11 (1) 125-134 doi:10.1127/ejm/11/1/0125
Garvie, Laurence A. J., Devouard, Bertrand, Groy, Thomas L., Camara, Fernando, Buseck, Peter R. (1999) Crystal structure of kanemite, NaHSi2O5 · 3H2O, from the Aris Phonolite, Namibia. American Mineralogist, 84 (7) 1170-1175 doi:10.2138/am-1999-7-820
Eypert-Blaison, C., Villiéras, F., Michot, L. J ., Pelletier, M., Humbert, B., Ghanbaja, J ., Yvon, J . (2002) Surface heterogeneity of kanemite, magadiite and kenyaite: a high-resolution gas adsorption study. Clay Minerals, 37 (3) 531-542 doi:10.1180/0009855023730056
Corredor, J. I., Cota, A., Pavon, E., Alba, M. D. (2013) Synthesis and characterization of kanemite from fluoride-containing media: Influence of the alkali cation. American Mineralogist, 98 (5) 1000-1007 doi:10.2138/am.2013.4372
Zubkova, N. V., Pekov, I. V., Pushcharovsky, D. Yu. (2014) A review of crystal chemistry of natural silicates of alkaline elements in the light of new structural data. Mineralogical Magazine, 78 (2) 253-265 doi:10.1180/minmag.2014.078.2.03
Schmidmair, Daniela, Kahlenberg, Volker, Többens, Daniel M., Schottenberger, Herwig, Jochem De Wit, , Griesser, Ulrich J. (2015) Temperature- and moisture-dependent powder X-ray diffraction studies of kanemite (NaSi2O4(OH)·3H2O) Mineralogical Magazine, 79 (1) 103-120 doi:10.1180/minmag.2015.079.1.09
Localities for Kanemite
Showing 6 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.
Chad (TL) | |
| Johan et al. (1972) |
India | |
| Shukla et al. (2021) |
Kenya | |
| Périnet et al. (1982) |
Namibia | |
| ... +3 other references |
Russia | |
| Pekov (2000) |
| Igor Pekov analysis |
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Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia