Dachiardite-K (original) (raw)

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Rare zeolite-group mineral

Dachiardite-K
General
Category Tectosilicate minerals, zeolite group
Formula K4(Si20Al4O48)·13H2O
IMA symbol Dac-K[1]
Crystal system Monoclinic Unknown space group
Unit cell a = 18.67, b = 7.51 c = 10.23 [Å], β = 107.79° (approximated)
Identification
Color Snow-white
Crystal habit Needle-like crystals in spherical aggregates
Cleavage (100), perfect
Fracture Stepped across
Tenacity Brittle
Mohs scale hardness 4
Density 2.18 (measured), 2.17 (calculated; approximated) [g/cm3]
Optical properties Biaxial (+)
Refractive index nα=1.48, nβ=1.48, nγ=1.48 (approximated)
Pleochroism No
2V angle 65o (measured)
Dispersion Distinct
References [2][3]

Dachiardite-K is a rare zeolite-group mineral with the formula K4(Si20Al4O48)•13H2O.[4][3] It is the potassium-analogue of dachiardite-Ca and dachiardite-Na, as suggested by the suffix "-K".[5][2] Dachiardite honors Italian geologist and mineralogist Antonio D'Achiardi.

Occurrence and association

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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.[3]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b "Dachiardite-K: Dachiardite-K mineral information and data". Mindat.org. Retrieved 2016-03-04.
  3. ^ a b c 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
  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
  5. ^ "dachiardite". Merriam-Webster Dictionary. Retrieved 30 May 2024.