Slawsonite
A valid IMA mineral species
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About Slawsonite
Chester Baker Slawson
Formula:
Sr(Al2Si2O8)
Colour:
Colourless, gray
Lustre:
Vitreous
Hardness:
5½ - 6½
Specific Gravity:
3.05
Crystal System:
Monoclinic
Member of:
Name:
Named by Dana T. Griffin, Paul H. Ribbe, and Gerald V. Gibbs in 1977 in honor of Chester "Chet" Baker Slawson [April 21, 1898 Greenville, Michigan, USA - March 12, 1964 Ann Arbor, Michigan, USA], Professor of Mineralogy, University of Michigan at Ann Arbor.
Type Locality:
Dimorph of:
Feldspar Group.
May form in course of heating of its monoclinic polymorph, UM1995-41-SiO:AlSr.
Four other polymorphic modifications: I2/c, P–3c, P63/mcm and Pm3m.
The structure has paracelsian topology; as such, the species may alternatively be grouped within "paracelsian group", alongside with danburite, paracelsian, pekovite, maleevite, hurlbutite, and strontiohurlbutite.
May form in course of heating of its monoclinic polymorph, UM1995-41-SiO:AlSr.
Four other polymorphic modifications: I2/c, P–3c, P63/mcm and Pm3m.
The structure has paracelsian topology; as such, the species may alternatively be grouped within "paracelsian group", alongside with danburite, paracelsian, pekovite, maleevite, hurlbutite, and strontiohurlbutite.
Unique Identifiers
Mindat ID:
3684
Long-form identifier:
mindat:1:1:3684:5
IMA Classification of Slawsonite
Approved
First published:
1977
Classification of Slawsonite
9.FA.50
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions
76.1.5.2
76 : TECTOSILICATES Al-Si Framework
1 : Al-Si Framework with Al-Si frameworks
76 : TECTOSILICATES Al-Si Framework
1 : Al-Si Framework with Al-Si frameworks
16.12.2
16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn
16 : Silicates Containing Aluminum and other Metals
12 : Aluminosilicates of Sr, Ba and Zn
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 |
|---|---|---|
| Sws | 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 Slawsonite
Vitreous
Transparency:
Transparent
Colour:
Colourless, gray
Streak:
White
Hardness:
5½ - 6½ on Mohs scale
Cleavage:
Distinct/Good
Good on {001}, fair to good on {100}.
Good on {001}, fair to good on {100}.
Fracture:
Sub-Conchoidal
Density:
3.05(1) g/cm3 (Measured) 3.044 g/cm3 (Calculated)
Optical Data of Slawsonite
Type:
Biaxial (-)
RI values:
nα = 1.570 - 1.573 nβ = 1.581 - 1.582 nγ = 1.585 - 1.586
2V:
Measured: 55° to 82°, Calculated: 60° to 66°
Max. Birefringence:
δ = 0.015
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.
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.
Surface Relief:
Moderate
Dispersion:
r < v medium
Optical Extinction:
Y ∧ c = 5°-11°.
Chemistry of Slawsonite
Mindat Formula:
Sr(Al2Si2O8)
Element Weights:
Elements listed:
Common Impurities:
Ti,Fe,Mg,Na,K,H2O
Crystallography of Slawsonite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/a
Cell Parameters:
a = 8.888(2) Å, b = 9.344(2) Å, c = 8.326(3) Å
β = 90.33(2)°
β = 90.33(2)°
Ratio:
a:b:c = 0.951 : 1 : 0.891
Unit Cell V:
691.46 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Tabular crystals, to 7 cm; in radial aggregates.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0000553 | Slawsonite | Griffen D T, Ribbe P H, Gibbs G V (1977) The structure of slawsonite, a strontium analog of paracelsian American Mineralogist 62 31-35 |  | 1977 | 0 | 293 | |
| 0002652 | Slawsonite | Benna P, Bruno E (2001) Single-crystal in situ high-temperature structural investigation on strontium feldspar American Mineralogist 86 690-696 | | 2001 | synthetic | 0 | 293 |
| 0002653 | Slawsonite | Benna P, Bruno E (2001) Single-crystal in situ high-temperature structural investigation on strontium feldspar American Mineralogist 86 690-696 | | 2001 | synthetic | 0 | 433 |
| 0002654 | Slawsonite | Benna P, Bruno E (2001) Single-crystal in situ high-temperature structural investigation on strontium feldspar American Mineralogist 86 690-696 | | 2001 | synthetic | 0 | 603 |
| 0002655 | Slawsonite | Benna P, Bruno E (2001) Single-crystal in situ high-temperature structural investigation on strontium feldspar American Mineralogist 86 690-696 | | 2001 | synthetic | 0 | 783 |
| 0002656 | Slawsonite | Benna P, Bruno E (2001) Single-crystal in situ high-temperature structural investigation on strontium feldspar American Mineralogist 86 690-696 | | 2001 | synthetic | 0 | 943 |
| 0004407 | Slawsonite | Benna P, Nestola F, Ballaran T B, Balic-Zunic T, Lundegaard L F, Bruno E (2007) The high-pressure structural configurations of Ca0.2Sr0.8Al2Si2O8 feldspar: The I-1-I2/c and I2/c-P2_1/c phase transitions American Mineralogist 92 1190-1199 | | 2007 | synthetic | 0.0001 | 293 |
| 0004408 | Slawsonite | Benna P, Nestola F, Ballaran T B, Balic-Zunic T, Lundegaard L F, Bruno E (2007) The high-pressure structural configurations of Ca0.2Sr0.8Al2Si2O8 feldspar: The I-1-I2/c and I2/c-P2_1/c phase transitions American Mineralogist 92 1190-1199 | | 2007 | synthetic | 3.2 | 293 |
| 0004409 | Slawsonite | Benna P, Nestola F, Ballaran T B, Balic-Zunic T, Lundegaard L F, Bruno E (2007) The high-pressure structural configurations of Ca0.2Sr0.8Al2Si2O8 feldspar: The I-1-I2/c and I2/c-P2_1/c phase transitions American Mineralogist 92 1190-1199 | | 2007 | synthetic | 4.4 | 293 |
| 0004410 | Slawsonite | Benna P, Nestola F, Ballaran T B, Balic-Zunic T, Lundegaard L F, Bruno E (2007) The high-pressure structural configurations of Ca0.2Sr0.8Al2Si2O8 feldspar: The I-1-I2/c and I2/c-P2_1/c phase transitions American Mineralogist 92 1190-1199 | | 2007 | synthetic | 6.2 | 293 |
| 0004411 | Slawsonite | Benna P, Nestola F, Ballaran T B, Balic-Zunic T, Lundegaard L F, Bruno E (2007) The high-pressure structural configurations of Ca0.2Sr0.8Al2Si2O8 feldspar: The I-1-I2/c and I2/c-P2_1/c phase transitions American Mineralogist 92 1190-1199 | | 2007 | synthetic | 7.4 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.231 Å | (100) |
| 3.938 Å | (80) |
| 2.930 Å | (50) |
| 2.087 Å | (40) |
| 3.720 Å | (35) |
| 2.949 Å | (35) |
| 2.679 Å | (35) |
Comments:
Sarusaka, Japan.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-𝑇 alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Slawsonite
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 122831-122833.
Geological Setting of Type Material:
Metamorphosed limestone.
Associated Minerals at Type Locality:
Synonyms of Slawsonite
Other Language Names for Slawsonite
Relationship of Slawsonite to other Species
Member of:
Other Members of Feldspar Group:
| Alkali Feldspar | A subgroup of the Feldspar Group, poor in calcium, and mostly rich in potassium. | |
| Buddingtonite | (NH4)(AlSi3O8) | Mon. 2 : P21 |
| Celsian | Ba(Al2Si2O8) | Mon. 2/m |
| Filatovite | K(Al,Zn)2(As,Si)2O8 | Mon. 2/m |
| Hexacelsian | BaAl2Si2O8 | Hex. 6/mmm (6/m 2/m 2/m) : P63/mcm |
| Kokchetavite | K(AlSi3O8) | Hex. 6/mmm (6/m 2/m 2/m) : P6/mcc |
| Kumdykolite | Na(AlSi3O8) | Orth. mmm (2/m 2/m 2/m) : Pnnm |
| Paracelsian | Ba(Al2Si2O8) | Mon. 2/m : P21/b |
| Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 | |
| Reedmergnerite | NaBSi3O8 | Tric. 1 : P1 |
| Svyatoslavite | Ca(Al2Si2O8) | Mon. 2 : P21 |
| Unnamed (New Ordered Member of the Alkali Feldspar Series) | KNa(Si6Al2)O16 | Mon. m |
Common Associates
Associated Minerals Based on Photo Data:
| 2 photos of Slawsonite associated with Diopside | CaMgSi2O6 |
| 1 photo of Slawsonite associated with Analcime | Na(AlSi2O6) · H2O |
| 1 photo of Slawsonite associated with Magnetite | Fe2+Fe3+2O4 |
| 1 photo of Slawsonite associated with Microcline | K(AlSi3O8) |
| 1 photo of Slawsonite associated with Titanium-bearing Magnetite | Fe2+(Fe3+,Ti)2O4 |
Related Minerals - Strunz-mindat Grouping
| 9.FA. | Hexacelsian | BaAl2Si2O8 |
| 9.FA. | Wodegongjieite | KCa3(Al7Si9)O32 |
| 9.FA.05 | Panunzite | (K,Na)AlSiO4 |
| 9.FA.05 | Yoshiokaite | (Ca,Na)[Al(Al,Si)O4] |
| 9.FA.05 | Nepheline | Na3K(Al4Si4O16) |
| 9.FA.05 | Trinepheline | NaAlSiO4 |
| 9.FA.05 | Davidsmithite | (Ca,◻)2Na6Al8Si8O32 |
| 9.FA.05 | Kaliophilite | KAlSiO4 |
| 9.FA.05 | Kalsilite | KAlSiO4 |
| 9.FA.05 | Carnegieite | NaAlSiO4 |
| 9.FA.05 | Megakalsilite | KAlSiO4 |
| 9.FA.05 | Trikalsilite | K2NaAl3(SiO4)3 |
| 9.FA.10 | Malinkoite | NaBSiO4 |
| 9.FA.15 | Virgilite | LiAlSi2O6 |
| 9.FA.25 | Lisitsynite | KBSi2O6 |
| 9.FA.30 | Ferrisanidine | K[Fe3+Si3O8] |
| 9.FA.30 | Buddingtonite | (NH4)(AlSi3O8) |
| 9.FA.30 | Rubicline | Rb(AlSi3O8) |
| 9.FA.30 | Monalbite | NaAlSi3O8 |
| 9.FA.30 | Microcline | K(AlSi3O8) |
| 9.FA.30 va | Germanate-celsian | BaAl2Ge2O8 |
| 9.FA.30 | Celsian | Ba(Al2Si2O8) |
| 9.FA.30 | Sanidine | K(AlSi3O8) |
| 9.FA.30 | Orthoclase | K(AlSi3O8) |
| 9.FA.35 | Reedmergnerite | NaBSi3O8 |
| 9.FA.35 | Albite | Na(AlSi3O8) |
| 9.FA.35 | Anorthite | Ca(Al2Si2O8) |
| 9.FA.40 | Paracelsian | Ba(Al2Si2O8) |
| 9.FA.45 | Svyatoslavite | Ca(Al2Si2O8) |
| 9.FA.45 | Kumdykolite | Na(AlSi3O8) |
| 9.FA.55 | Lisetite | CaNa2Al4Si4O16 |
| 9.FA.60 | Stronalsite | Na2SrAl4Si4O16 |
| 9.FA.60 | Banalsite | Na2BaAl4Si4O16 |
| 9.FA.65 | Maleevite | BaB2Si2O8 |
| 9.FA.65 | Pekovite | SrB2Si2O8 |
| 9.FA.65 | Danburite | CaB2Si2O8 |
| 9.FA.70 | Liebermannite | KAlSi3O8 |
| 9.FA.70 | Lingunite | (Na,Ca)AlSi3O8 |
| 9.FA.70 | Stöfflerite | CaAl2Si2O8 |
| 9.FA.75 | Pfaffenbergite | KNa3(Al4Si12)O32 |
| 9.FA.75 | Kokchetavite | K(AlSi3O8) |
Fluorescence of Slawsonite
May fluoresce intense pinkish red-purple under SW UV
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 Slawsonite
mindat.org URL:
https://www.mindat.org/min-3684.html
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References for Slawsonite
Reference List:
Griffen, Dana T., Ribbe, P. H., Gibbs, G. V. (1977) The structure of slawsonite, a strontium analog of paracelsian. American Mineralogist, 62 (1-2) 31-35
Franke, W., Ghobarkar, H., Heimann, R.B. (1979) The morphology of hydrothermally grown strontium paracelsian. Journal of Crystal Growth, 46 (4). 474-478 doi:10.1016/0022-0248(79)90032-0
Tagai, T., Hoshi, T., Suzuki, M., Kato, A., Matsubara, S. (1995) A new modification of slawsonite, SrAl2Si2O8: Its structure and phase transition. Zeitschrift für Kristallographie, 210 (10). doi:10.1524/zkri.1995.210.10.741
Localities for Slawsonite
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 | |
| Liferovich et al. (2006) |
Czech Republic | |
| Tasáryová et al. (2014) |
| Matýsek et al. (2016) |
| Matýsek et al. (2016) |
| Matýsek et al. (2016) |
Japan | |
| Komuro Minerals specimen +1 other reference |
| Kato et al. (1986) |
| Mineralogical Journal Vol. 13 (1986) |
| Matsubara (1985) +1 other reference |
| Miyajima +1 other reference |
Spain | |
| Ковальчук et al. (2014) |
USA | |
| RocK H. Currier systematic species ... |
| Griffen et al. (1977) +1 other reference |
| Phillips et al. (2008, December) |
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Řepiště teschenite outcrops, Řepiště, Frýdek-Místek District, Moravian-Silesian Region, Czech Republic