Chemistry:Dachiardite-K

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Dachiardite-K
General
CategoryTectosilicate, Zeolite
Formula
(repeating unit)
K4(Si20Al4O48)·13H2O
Crystal systemMonoclinic
Unknown space group
Unit cella = 18.67, b = 7.51
c = 10.23 [Å], β = 107.79° (approximated)
Identification
ColorSnow-white
Crystal habitNeedle-like crystals in spherical aggregates
Cleavage(100), perfect
FractureStepped across
TenacityBrittle
Mohs scale hardness4
Density2.18 (measured), 2.17 (calculated; approximated) [g/cm3]
Optical propertiesBiaxial (+)
Refractive indexnα=1.48, nβ=1.48, nγ=1.48 (approximated)
PleochroismNo
2V angle65o (measured)
DispersionDistinct
References[1][2]

Dachiardite-K is a rare zeolite-group mineral with the formula K4(Si20Al4O48)•13H2O.[4][2] It is the potassium-analogue of dachiardite-Ca and dachiardite-Na, as suggested by the suffix "-K".[1]

Occurrence and association

Dachiardite-K was discovered in opal-chalcedony veins in Eastern Rhodopes, Bulgaria. It is associated with barite, calcite, clinoptilolite-Ca, clinoptilolite-K, celadonite, dachiardite-Ca, dachiardite-Na, ferrierite-K, ferrierite-Mg, ferrierite-Na, mordenite, and smectite.[2]

References

  1. 1.0 1.1 "Dachiardite-K: Dachiardite-K mineral information and data". http://www.mindat.org/min-46790.html. Retrieved 2016-03-04. 
  2. 2.0 2.1 2.2 Encheva, S., Petrov, P., Chukanov, N., and Pekov, I., 2015. Dachiardite-K from the area of Austa village, Momchilgrad municipality, Eastern Rhodopes – a new mineral species of zeolite group. Bulgarian Geological Society, National Conference with international participation “GEOSCIENCES 2015”, 10-11 Dec 2015, Sofia, Bulgaria; pp. 17-18
  3. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine 85 (3): 291–320. doi:10.1180/mgm.2021.43. Bibcode2021MinM...85..291W. 
  4. Chukanov, N.V., Encheva, S., Petrov, P., Pekov, I.V., Belakovskiy, D.I., Britvin, S.N., and Aksenov, S.M., 2015. Dachiardite-K, IMA 2015-041. CNMNC Newsletter No. 27, October 2015, 1224; Mineralogical Magazine 79, 1229–1236