Kokchetavite (original) (raw)

A valid IMA mineral species

Specific Gravity:

2.45 (Calculated)

Name:

Named after the Kokchetav Massif, Kazakhstan that includes the type locality.

Metastable high-pressure polymorph. Found within a multiphase inclusion in a clinopyroxene and garnet. Formed likely either due to (1) a precipitate of infiltrated K-rich melt, during exhumation, or (2) dehydration of the HP phase 'K-cymrite'.

The K4-analogue of pfaffenbergite; the K4(Al4Si12)-analogue of wodegongjieite. The analogy towards pfaffenbergite may be imaged after multiplication of the kokchetavite formula by 4 → K4(Al4Si12)O32.

Unique IdentifiersHide

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Long-form identifier:

mindat:1:1:27460:1

3eaf4131-21cb-47e4-9f26-cefbbf99fef1

IMA Classification of KokchetaviteHide

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Classification of KokchetaviteHide

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9.FA.75

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H2O
A : Tektosilicates without additional non-tetrahedral anions

Mineral SymbolsHide

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As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of KokchetaviteHide

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Density:

2.45 g/cm3 (Calculated)

Chemistry of KokchetaviteHide

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Mindat Formula:

K(AlSi3O8)

Crystallography of KokchetaviteHide

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Class (H-M):

6/m m m _(_6/_m_2/_m_2/m ) - Dihexagonal Dipyramidal

Cell Parameters:

a = 10.5757(3) Å, c = 15.6404(6) Å

Comment:

Data from Romanenko et al. (2021). Originally assumed to have P6/mmm, with a = 5.27 and c = 7.82 Å.

X-Ray Powder DiffractionHide

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Powder Diffraction Data:

Comments:

No PXRD in type description. The data above are lines from the SAED pattern. Data are from the type description. No intensities are given.

Geological EnvironmentHide

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Type Occurrence of KokchetaviteHide

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General Appearance of Type Material:

3-7 micrometer plates and prisms.

Place of Conservation of Type Material:

National Museum of Natural Science, Taichung, Taiwan.

Geological Setting of Type Material:

Ultrahigh-grade granitic and biotite gneiss.

Associated Minerals at Type Locality:

Synonyms of KokchetaviteHide

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Other Language Names for KokchetaviteHide

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Relationship of Kokchetavite to other SpeciesHide

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Other Members of this group:

Related Minerals - Strunz-mindat GroupingHide

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Other InformationHide

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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 KokchetaviteHide

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References for KokchetaviteHide

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Reference List:

Hwang, Shyh-Lung, Shen, Pouyan, Chu, Hao-Tsu, Yui, Tzen-Fu, Liou, Juhn G., Sobolev, Nikolay V., Zhang, Ru-Yuan, Shatsky, Vladislav S., Zayachkovsky, Anton A. (2004) Kokchetavite: a new potassium-feldspar polymorph from the Kokchetav ultrahigh-pressure terrane. Contributions to Mineralogy and Petrology, 148 (3) 380-389 doi:10.1007/s00410-004-0610-2

Hwang, S.L., Yui, T.F., Chu, H.T., Shen, P., Liou, J.G., Sobolev, N.V. (2013): Oriented kokchetavite compound rods in clinopyroxene of Kokchetav ultrahigh-pressure rocks. Journal of Asian Earth Sciences, 63, 56-69.

Romanenko, Alexandr V., Rashchenko, Sergey V., Sokol, Alexander G., Korsakov, Andrey V., Seryotkin, Yurii V., Glazyrin, Konstantin V., Musiyachenko, Kira (2021) Crystal structures of K-cymrite and kokchetavite from single-crystal X-ray diffraction. American Mineralogist, 106 (3) 404-409 doi:10.2138/am-2020-7407

Romanenko, Alexandr V., Rashchenko, Sergey V., Korsakov, Andrey V., Sokol, Alexander G., Kokh, Konstantin A. (2024) Compressibility and pressure-induced structural evolution of kokchetavite, hexagonal polymorph of KAlSi3O8, by single-crystal X-ray diffraction. American Mineralogist, 109 (7) 1284-1291 doi:10.2138/am-2023-9120

Localities for KokchetaviteHide

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This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

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- 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.