Tounkite
A valid IMA mineral species
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About Tounkite
Formula:
(Na,Ca,K)8(Si6Al6)O24(SO4)2Cl · 0.5H2O
(x, y, n < 1); the Mindat formula is a simplified version of the simplified crystallochemical formula from the abstract (Chukanov et al. 2024): (Na3.89–5.18K0.15–1.64Ca2.30–2.58(Al6Si6O24)(SO4,S52−,S4)2−x (Cl−,HS−)1+y·nH2O (x, y, n < 1); may bear trace S2·− and S3·− radicals' admixtures;
formerly given as (Na,Ca,K)8(Al6Si6O24)(SO4)2Cl.H2O
formerly given as (Na,Ca,K)8(Al6Si6O24)(SO4)2Cl.H2O
Colour:
Green to yellowish-green, glass-green with a yellowish or gray tint
Lustre:
Vitreous
Hardness:
5 - 5½
Specific Gravity:
2.557
Crystal System:
Hexagonal
Member of:
Name:
Named after its discovery locality, Tounka Valley, Baikal region, Russia.
Co-Type Localities:
Dimorph of:
Tounkite is defined as a 12-layer cancrinite-group mineral with the ordered aluminosilicate framework formed by the CBCBCACBCACA stacking sequence of layers composed of six-membered rings of tetrahedra, with the simplified general formula
(Na,Ca,K)8[Al6Si6O24](SO42−,S4,S52−)2(Cl−,HS−)·nH2O, minor admixtures of S3− and/or S2− radical anions, and wide variations of the contents of extra-framework K+, S4 and S52−. The framework contains liottite and Losod cages, as well as columns of cancrinite cages.
The S3−, S52−, S4 and S3− extra-framework species are the main chromophores determining variations of the tounkite color.
Crystallizes under highly reducing conditions.
(Na,Ca,K)8[Al6Si6O24](SO42−,S4,S52−)2(Cl−,HS−)·nH2O, minor admixtures of S3− and/or S2− radical anions, and wide variations of the contents of extra-framework K+, S4 and S52−. The framework contains liottite and Losod cages, as well as columns of cancrinite cages.
The S3−, S52−, S4 and S3− extra-framework species are the main chromophores determining variations of the tounkite color.
Crystallizes under highly reducing conditions.
Unique Identifiers
Mindat ID:
4002
Long-form identifier:
mindat:1:1:4002:6
Similar Names
| Tankite (of Haidinger) | A synonym of Xenotime-(Y) |
IMA Classification of Tounkite
Approved
IMA Formula:
(Na,Ca,K)8(Si6Al6)O24(S6+O4)2Cl·0.5H2O
Approval year:
1990
First published:
1992
Classification of Tounkite
9.FB.05
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
B : Tektosilicates with additional anions
9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
B : Tektosilicates with additional anions
76.2.5.14
76 : TECTOSILICATES Al-Si Framework
2 : Al-Si Framework Feldspathoids and related species
76 : TECTOSILICATES Al-Si Framework
2 : Al-Si Framework Feldspathoids and related species
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 |
|---|---|---|
| Tou | 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 Tounkite
Vitreous
Transparency:
Transparent
Colour:
Green to yellowish-green, glass-green with a yellowish or gray tint
Comment:
The observed differences in the colors are associated with the different amounts of polysulfide groups contained in them. Both samples contain different amounts S52− anions, which are a yellow chromophore, and minor admixtures of the S3− radical anions, which are a very strong blue chromophore, Sample 2 contains significant amounts of S4
molecules (a weak red chromophore) and Sample 3 contains S2− radical anions (a yellow chromophore). Thus, the blue color of Sample 2 is mainly related to the presence of S3− and S4, whereas the green color of Sample 3 is due to the combination of S3−, S2− and S52−.
molecules (a weak red chromophore) and Sample 3 contains S2− radical anions (a yellow chromophore). Thus, the blue color of Sample 2 is mainly related to the presence of S3− and S4, whereas the green color of Sample 3 is due to the combination of S3−, S2− and S52−.
Streak:
White
Hardness:
5 - 5½ on Mohs scale
Cleavage:
Distinct/Good
{1010}, fair.
{1010}, fair.
Density:
2.557(4) g/cm3 (Measured) 2.60 g/cm3 (Calculated)
Optical Data of Tounkite
Type:
Uniaxial (+)
RI values:
nω = 1.528 nε = 1.543
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
Pleochroism:
Visible
Comments:
O = colorless; E = yellow-green.
Chemistry of Tounkite
Mindat Formula:
(Na,Ca,K)8(Si6Al6)O24(SO4)2Cl · 0.5H2O
(x, y, n < 1); the Mindat formula is a simplified version of the simplified crystallochemical formula from the abstract (Chukanov et al. 2024): (Na3.89–5.18K0.15–1.64Ca2.30–2.58(Al6Si6O24)(SO4,S52−,S4)2−x (Cl−,HS−)1+y·nH2O (x, y, n < 1); may bear trace S2·− and S3·− radicals' admixtures;
formerly given as (Na,Ca,K)8(Al6Si6O24)(SO4)2Cl.H2O
(x, y, n < 1); the Mindat formula is a simplified version of the simplified crystallochemical formula from the abstract (Chukanov et al. 2024): (Na3.89–5.18K0.15–1.64Ca2.30–2.58(Al6Si6O24)(SO4,S52−,S4)2−x (Cl−,HS−)1+y·nH2O (x, y, n < 1); may bear trace S2·− and S3·− radicals' admixtures;
formerly given as (Na,Ca,K)8(Al6Si6O24)(SO4)2Cl.H2O
Element Weights:
Crystallography of Tounkite
Crystal System:
Hexagonal
Class (H-M):
622 - Trapezohedral
Space Group:
P6222
Cell Parameters:
a = 12.843(3) Å, c = 32.239(8) Å
Ratio:
a:c = 1 : 2.51
Unit Cell V:
4,605.16 ų (Calculated from Unit Cell)
Z:
6
Twinning:
Polysynthetic twinning is a specific feature of tounkite. The boundaries of twin components, connected by a rotation of 180° around the [001] axis, run perpendicular to this axis, along the planes of the six-membered rings. A large 10-layed cage formed at the border between twin components, connected by a rotation of 180° around the [001] axis, which may host the large S52− anion
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.711 Å | (100) |
| 3.314 Å | (80) |
| 4.842 Å | (40) |
| 2.687 Å | (25) |
| 2.139 Å | (25) |
| 3.035 Å | (20) |
| 2.988 Å | (16) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Tounkite
Co-Type Localities:
General Appearance of Type Material:
elongated crystals, to 1 cm.
Place of Conservation of Type Material:
Mineralogical Museum, St. Petersburg University, St. Petersburg; A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia.
Associated Minerals at Type Locality:
Synonyms of Tounkite
Other Language Names for Tounkite
Relationship of Tounkite to other Species
Member of:
Other Members of Cancrinite Group:
| Afghanite | (Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6 | Trig. 3m : P31c |
| Alloriite | (Na,Ca,K)26Ca4(Al6Si6O24)4(SO4)6Cl6 | Trig. 3m : P31c |
| Balliranoite | (Na,K)6Ca2(Si6Al6O24)Cl2(CO3) | Hex. 6 : P63 |
| Betzite | Na6Ca2(Al6Si6O24)Cl4 | Hex. 6 : P63 |
| Biachellaite | (Na,Ca,K)8(Al6Si6O24)(SO4)2(OH)0.5 · H2O | Trig. 3 : P3 |
| Bystrite | (Na,K)7Ca(Al6Si6O24)(S5)Cl | Trig. 3m : P31c |
| Cancrinite | (Na,Ca,◻)8(Al6Si6O24)(CO3,SO4)2 · 2H2O | Hex. 6 : P63 |
| Cancrisilite | Na7(Al5Si7O24)(CO3) · 3H2O | Hex. 6mm : P63mc |
| Carbobystrite | Na8(Al6Si6O24)(CO3) · 3.5H2O | Trig. 3m : P31c |
| Davyne | (Na,K)6Ca2(Al6Si6O24)(Cl2,SO4)2 | Hex. 6/m : P63/m |
| Depmeierite | Na8(Al6Si6O24)(PO4,CO3)1-x · 3H2O (x<0.5) | Hex. 6 : P63 |
| Fantappièite | [Na82.5Ca33K16.5](Si99Al99O396)(SO4)33 · 4H2O | Trig. 3 : R3 |
| Farneseite | (Na,Ca,K)56(Al6Si6O24)7(SO4)12 · 6H2O | Hex. 6/m : P63/m |
| Franzinite | (Na,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2O | Hex. |
| Giuseppettite | (Na,K,Ca)7-8(Al6Si6O24)(SO4,Cl)1-2 | Trig. 3m : P31c |
| Hydroxycancrinite | Na8(Al6Si6O24)(OH)2 · 2H2O | Hex. 6 : P63 |
| Kircherite | Na5Ca2K(Al6Si6O24)(SO4)2 · 0.33H2O | Trig. 32 : R32 |
| Kyanoxalite | Na7(Al6-xSi6+xO24)(C2O4)0.5+x · 5H2O (0 < x < 0.5) | Hex. 6 : P63 |
| Liottite | (Na,K)16Ca8(Al6Si6O24)3(SO4)5Cl4 | Hex. 6 : P6 |
| Marinellite | (Na,K)42Ca6(Al6Si6O24)6(SO4)8Cl2 · 3H2O | Trig. 3m : P31c |
| Microsommite | Na4K2Ca2(Al6Si6O24)(SO4)Cl2 | Hex. 622 : P6322 |
| Pitiglianoite | Na6K2(Al6Si6O24)(SO4) · 2H2O | Hex. 6 : P63 |
| Quadridavyne | (Na,K)6Ca2(Al6Si6O24)Cl4 | Hex. 6/m : P63/m |
| Sacrofanite | (Na61K19Ca32)(Si84Al84O336)(SO4)26Cl2F6 · 2H2O | Hex. |
| Steudelite | Na3(K17Ca7)Ca4(Al24Si24O96)(SO3)6F6 · 4H2O | Hex. 6m2 : P62c |
| Sulfhydrylbystrite | Na5K2Ca[Al6Si6O24](S5)2(SH) | Trig. 3m : P31c |
| 'UM2004-48-SiO:AlClCaNaS' | (Na,Ca)8(Si6Al6)O24(SO4)1.7Cl1.3 | |
| 'UM2009-23-SiO:AlCCaClHKNaS' | (Na,Ca)24K10[(Si,Al)60O120](SO4)5.6Cl1.5(CO3)0.4 · 11H2O | Trig. 3 : P3 |
| Vishnevite | (Na,K)8(Al6Si6O24)(SO4,CO3) · 2H2O | Hex. 6 : P63 |
Common Associates
Associations Based on Photo Data:
| 3 photos of Tounkite associated with Diopside | CaMgSi2O6 |
| 3 photos of Tounkite associated with Calcite | CaCO3 |
| 2 photos of Tounkite associated with Afghanite | (Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6 |
| 2 photos of Tounkite associated with Pyrite | FeS2 |
| 2 photos of Tounkite associated with Lazurite | Na7Ca(Al6Si6O24)(SO4)(S3) · H2O |
| 2 photos of Tounkite associated with Fluorapatite | Ca5(PO4)3F |
| 2 photos of Tounkite associated with Chabazite-Ca | (Ca,K2,Na2)2[Al2Si4O12]2 · 12H2O |
Related Minerals - Strunz-mindat Grouping
| 9.FB. | Perchukite-(Y) | PbYAsSi2O8 |
| 9.FB. | Åsgruvanite-(Ce) | Ce16Ca5Al(SiO4)6(AsO3)8(CO3)2Cl4F3(OH)2 |
| 9.FB. | Steudelite | Na3(K17Ca7)Ca4(Al24Si24O96)(SO3)6F6 · 4H2O |
| 9.FB. | Wenlanzhangite-(Y) | Y2V3+2V4+2(SiO4)2O4(OH)4 |
| 9.FB. | Slyudyankaite | Na28Ca4(Si24Al24O96)(SO4)6(S6)1/3(CO2) · 2H2O |
| 9.FB. | Bolotinaite | (Na7◻)(Al6Si6O24)F · 4H2O |
| 9.FB. | Sapozhnikovite | Na8(Al6Si6O24)(HS)2 |
| 9.FB. | Betzite | Na6Ca2(Al6Si6O24)Cl4 |
| 9.FB.05 | Quadridavyne | (Na,K)6Ca2(Al6Si6O24)Cl4 |
| 9.FB.05 | Sulfhydrylbystrite | Na5K2Ca[Al6Si6O24](S5)2(SH) |
| 9.FB.05 | Marinellite | (Na,K)42Ca6(Al6Si6O24)6(SO4)8Cl2 · 3H2O |
| 9.FB.05 | Afghanite | (Na,K)22Ca10(Si24Al24O96)(SO4)6Cl6 |
| 9.FB.05 | Bystrite | (Na,K)7Ca(Al6Si6O24)(S5)Cl |
| 9.FB.05 | Franzinite | (Na,K)6Ca2(Al6Si6O24)(SO4)2 · 0.5H2O |
| 9.FB.05 | Kyanoxalite | Na7(Al6-xSi6+xO24)(C2O4)0.5+x · 5H2O (0 < x < 0.5) |
| 9.FB.05 | Vishnevite | (Na,K)8(Al6Si6O24)(SO4,CO3) · 2H2O |
| 9.FB.05 | Farneseite | (Na,Ca,K)56(Al6Si6O24)7(SO4)12 · 6H2O |
| 9.FB.05 | Alloriite | (Na,Ca,K)26Ca4(Al6Si6O24)4(SO4)6Cl6 |
| 9.FB.05 | Liottite | (Na,K)16Ca8(Al6Si6O24)3(SO4)5Cl4 |
| 9.FB.05 | Depmeierite | Na8(Al6Si6O24)(PO4,CO3)1-x · 3H2O (x<0.5) |
| 9.FB.05 | Biachellaite | (Na,Ca,K)8(Al6Si6O24)(SO4)2(OH)0.5 · H2O |
| 9.FB.05 | Cancrinite | (Na,Ca,◻)8(Al6Si6O24)(CO3,SO4)2 · 2H2O |
| 9.FB.05 | Cancrisilite | Na7(Al5Si7O24)(CO3) · 3H2O |
| 9.FB.05 | Fantappièite | [Na82.5Ca33K16.5](Si99Al99O396)(SO4)33 · 4H2O |
| 9.FB.05 | Carbobystrite | Na8(Al6Si6O24)(CO3) · 3.5H2O |
| 9.FB.05 | Microsommite | Na4K2Ca2(Al6Si6O24)(SO4)Cl2 |
| 9.FB.05 | Pitiglianoite | Na6K2(Al6Si6O24)(SO4) · 2H2O |
| 9.FB.05 | Balliranoite | (Na,K)6Ca2(Si6Al6O24)Cl2(CO3) |
| 9.FB.05 | Giuseppettite | (Na,K,Ca)7-8(Al6Si6O24)(SO4,Cl)1-2 |
| 9.FB.05 | Sacrofanite | (Na61K19Ca32)(Si84Al84O336)(SO4)26Cl2F6 · 2H2O |
| 9.FB.05 | Kircherite | Na5Ca2K(Al6Si6O24)(SO4)2 · 0.33H2O |
| 9.FB.05 | Hydroxycancrinite | Na8(Al6Si6O24)(OH)2 · 2H2O |
| 9.FB.05 | Davyne | (Na,K)6Ca2(Al6Si6O24)(Cl2,SO4)2 |
| 9.FB.10 | Haüyne | Na3Ca(Si3Al3)O12(SO4) |
| 9.FB.10 | Lazurite | Na7Ca(Al6Si6O24)(SO4)(S3) · H2O |
| 9.FB.10 | Danalite | Be3Fe2+4(SiO4)3S |
| 9.FB.10 | Helvine | Be3Mn2+4(SiO4)3S |
| 9.FB.10 | Kamaishilite | Ca2(Al2SiO6)(OH)2 |
| 9.FB.10 | Sodalite | Na4(Si3Al3)O12Cl |
| 9.FB.10 | Nosean | Na8(Al6Si6O24)(SO4) · H2O |
| 9.FB.10 | Genthelvite | Be3Zn4(SiO4)3S |
| 9.FB.10 | Bicchulite | Ca2(Al2SiO6)(OH)2 |
| 9.FB.10 | Tsaregorodtsevite | (N(CH3)4)(AlSi5O12) |
| 9.FB.10 | Vladimirivanovite | Na6Ca2(Al6Si6O24)(SO4,S3,S2,Cl)2 · H2O |
| 9.FB.10 | Tugtupite | (BeAlSi)Na4(SiO4)3Cl |
| 9.FB.15 | Marialite | Na4Al3Si9O24Cl |
| 9.FB.15 | Meionite | Ca4Al6Si6O24CO3 |
| 9.FB.15 | Silvialite | (Ca,Na)4(Al6Si6O24)(SO4,CO3) |
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 Tounkite
mindat.org URL:
https://www.mindat.org/min-4002.html
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References for Tounkite
Reference List:
Hassan, I., Grundy, H. D. (1984) The crystal structures of sodalite-group minerals. Acta Crystallographica Section B Structural Science, 40 (1) 6-13 doi:10.1107/s0108768184001683
Jambor, John L., Grew, Edward S. (1994) New Mineral Names. American Mineralogist, 79 (1-2) 185-189 p.187
Ballirano, P., Maras, A., Buseck, P. R. (1996) Crystal chemistry and IR spectroscopy of Cl- and SO4-bearing cancrinite-like minerals. American Mineralogist, 81 (7) 1003-1012 doi:10.2138/am-1996-7-822
Localities for Tounkite
Showing 2 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.
Russia (TL) | |
| Ivanov et al. (1992) +2 other references |
| Ivanov et al. (1992) +3 other references |
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Malo-Bystrinskoe lazurite deposit, Malaya Bystraya River Valley, Slyudyansky District, Irkutsk Oblast, Russia